title: Undefined method 'link_to_add\remove' for #<SimpleForm::FormBuilder>
body: <p>Ive been doing some research and I can't seem to find what Im doing wrong.</p>
  
  <p>I have installed simple_form and nested_form gems but when I use either link_to_add or remove I get the same error. </p>
  
  <p>Heres the code</p>
  
  <p>/fields.html.erb</p>
  
  <pre><code>    &lt;%= render 'shared/error_messages', :object =&gt; f.object %&gt;
      &lt;%= f.input :nombre_cliente, :label =&gt; 'Nombre del cliente:', :as =&gt; :string %&gt;
      &lt;%= f.input :mail_cliente, :label =&gt; 'E-mail del cliente:', :as =&gt; :string %&gt;
      &lt;%= f.input :empresa_cliente, :label =&gt; 'Empresa:', :as =&gt; :string %&gt;
      &lt;%= f.input :confirmada, :label =&gt; 'Ha sido confirmada por el cliente.' %&gt;
      &lt;%= f.input :confirmacion_cliente, :label =&gt; 'Fecha de confirmacion por el cliente:', :as =&gt; :date %&gt;
      &lt;b&gt;something here&lt;/b&gt;
      &lt;/br&gt;&lt;/br&gt;
      &lt;%= f.simple_fields_for :producto_de_cotizacion do |productos| %&gt;
       &lt;%= productos.input :nombre %&gt;
       &lt;%= productos.input :descripcion %&gt;
       &lt;%= productos.input :precio%&gt;
       &lt;%= productos.link_to_remove("Eliminar producto") %&gt;
     &lt;% end %&gt;
     &lt;%= f.link_to_add "Agregar producto", :producto_de_cotizacion %&gt;
  </code></pre>
  
  <p>Some of it is in spanish but I think its understandable</p>
  
  <p>Here is the actual error Im getting:</p>
  
  <blockquote>
    <p>undefined method `link_to_remove' for &lt; SimpleForm::FormBuilder:0x9ccf37c></p>
  </blockquote>
  
  <p>That is the entirety of _fields.html.erb, but its being called by the new.html.erb and the edit.html.erb files which are basically identical, Ill post the edit file:</p>
  
  <pre><code>&lt;h1&gt;Agregar Cotizacion&lt;/h1&gt;
  &lt;div id='admin_view'&gt;
    &lt;%= simple_form_for @cotizacion, :html =&gt; {:multipart =&gt; true} do |f| %&gt;
    &lt;%= render "fields", :f =&gt; f %&gt;
    &lt;%= f.button :submit, 'Actualizar Cotizacion' %&gt;
        &lt;% end%&gt;
  &lt;/div&gt;
  </code></pre>
  
  <p>After changing it to simple_nested_form I get a new error:</p>
  
  <pre><code>undefined method `klass' for nil:NilClass
  </code></pre>
  
  <p>and heres the stack</p>
  
  <pre><code>activesupport (3.0.7) lib/active_support/whiny_nil.rb:48:in `method_missing'
  /home/peanut/.rvm/gems/ruby-1.9.2-p180/bundler/gems/nested_form-57f32788f195/lib/nested_form/builder_mixin.rb:23:in `block in link_to_add'
  /home/peanut/.rvm/gems/ruby-1.9.2-p180/bundler/gems/nested_form-57f32788f195/lib/nested_form/view_helper.rb:37:in `call'
  /home/peanut/.rvm/gems/ruby-1.9.2-p180/bundler/gems/nested_form-57f32788f195/lib/nested_form/view_helper.rb:37:in `block in after_nested_form_callbacks'
  /home/peanut/.rvm/gems/ruby-1.9.2-p180/bundler/gems/nested_form-57f32788f195/lib/nested_form/view_helper.rb:36:in `map'
  /home/peanut/.rvm/gems/ruby-1.9.2-p180/bundler/gems/nested_form-57f32788f195/lib/nested_form/view_helper.rb:36:in `after_nested_form_callbacks'
  /home/peanut/.rvm/gems/ruby-1.9.2-p180/bundler/gems/nested_form-57f32788f195/lib/nested_form/view_helper.rb:13:in `simple_nested_form_for'
  app/views/cotizacions/edit.html.erb:3:in `_app_views_cotizacions_edit_html_erb__855809706_86735240_354753338'
  actionpack (3.0.7) lib/action_view/template.rb:135:in `block in render'
  activesupport (3.0.7) lib/active_support/notifications.rb:54:in `instrument'
  actionpack (3.0.7) lib/action_view/template.rb:127:in `render'
  actionpack (3.0.7) lib/action_view/render/rendering.rb:59:in `block in _render_template'
  activesupport (3.0.7) lib/active_support/notifications.rb:52:in `block in instrument'
  activesupport (3.0.7) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
  activesupport (3.0.7) lib/active_support/notifications.rb:52:in `instrument'
  actionpack (3.0.7) lib/action_view/render/rendering.rb:56:in `_render_template'
  actionpack (3.0.7) lib/action_view/render/rendering.rb:26:in `render'
  actionpack (3.0.7) lib/abstract_controller/rendering.rb:115:in `_render_template'
  actionpack (3.0.7) lib/abstract_controller/rendering.rb:109:in `render_to_body'
  actionpack (3.0.7) lib/action_controller/metal/renderers.rb:47:in `render_to_body'
  actionpack (3.0.7) lib/action_controller/metal/compatibility.rb:55:in `render_to_body'
  actionpack (3.0.7) lib/abstract_controller/rendering.rb:102:in `render_to_string'
  actionpack (3.0.7) lib/abstract_controller/rendering.rb:93:in `render'
  actionpack (3.0.7) lib/action_controller/metal/rendering.rb:17:in `render'
  actionpack (3.0.7) lib/action_controller/metal/instrumentation.rb:40:in `block (2 levels) in render'
  activesupport (3.0.7) lib/active_support/core_ext/benchmark.rb:5:in `block in ms'
  /home/peanut/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/benchmark.rb:309:in `realtime'
  activesupport (3.0.7) lib/active_support/core_ext/benchmark.rb:5:in `ms'
  actionpack (3.0.7) lib/action_controller/metal/instrumentation.rb:40:in `block in render'
  actionpack (3.0.7) lib/action_controller/metal/instrumentation.rb:78:in `cleanup_view_runtime'
  activerecord (3.0.7) lib/active_record/railties/controller_runtime.rb:15:in `cleanup_view_runtime'
  actionpack (3.0.7) lib/action_controller/metal/instrumentation.rb:39:in `render'
  meta-tags (1.2.4) lib/meta_tags/controller_helper.rb:28:in `render_with_meta_tags'
  actionpack (3.0.7) lib/action_controller/metal/implicit_render.rb:14:in `default_render'
  actionpack (3.0.7) lib/action_controller/metal/implicit_render.rb:6:in `send_action'
  actionpack (3.0.7) lib/abstract_controller/base.rb:150:in `process_action'
  actionpack (3.0.7) lib/action_controller/metal/rendering.rb:11:in `process_action'
  actionpack (3.0.7) lib/abstract_controller/callbacks.rb:18:in `block in process_action'
  activesupport (3.0.7) lib/active_support/callbacks.rb:451:in `_run__761686272__process_action__750077467__callbacks'
  activesupport (3.0.7) lib/active_support/callbacks.rb:410:in `_run_process_action_callbacks'
  activesupport (3.0.7) lib/active_support/callbacks.rb:94:in `run_callbacks'
  actionpack (3.0.7) lib/abstract_controller/callbacks.rb:17:in `process_action'
  actionpack (3.0.7) lib/action_controller/metal/instrumentation.rb:30:in `block in process_action'
  activesupport (3.0.7) lib/active_support/notifications.rb:52:in `block in instrument'
  activesupport (3.0.7) lib/active_support/notifications/instrumenter.rb:21:in `instrument'
  activesupport (3.0.7) lib/active_support/notifications.rb:52:in `instrument'
  actionpack (3.0.7) lib/action_controller/metal/instrumentation.rb:29:in `process_action'
  actionpack (3.0.7) lib/action_controller/metal/rescue.rb:17:in `process_action'
  actionpack (3.0.7) lib/abstract_controller/base.rb:119:in `process'
  actionpack (3.0.7) lib/abstract_controller/rendering.rb:41:in `process'
  actionpack (3.0.7) lib/action_controller/metal.rb:138:in `dispatch'
  actionpack (3.0.7) lib/action_controller/metal/rack_delegation.rb:14:in `dispatch'
  actionpack (3.0.7) lib/action_controller/metal.rb:178:in `block in action'
  actionpack (3.0.7) lib/action_dispatch/routing/route_set.rb:62:in `call'
  actionpack (3.0.7) lib/action_dispatch/routing/route_set.rb:62:in `dispatch'
  actionpack (3.0.7) lib/action_dispatch/routing/route_set.rb:27:in `call'
  rack-mount (0.6.14) lib/rack/mount/route_set.rb:148:in `block in call'
  rack-mount (0.6.14) lib/rack/mount/code_generation.rb:93:in `block in recognize'
  rack-mount (0.6.14) lib/rack/mount/code_generation.rb:89:in `optimized_each'
  rack-mount (0.6.14) lib/rack/mount/code_generation.rb:92:in `recognize'
  rack-mount (0.6.14) lib/rack/mount/route_set.rb:139:in `call'
  actionpack (3.0.7) lib/action_dispatch/routing/route_set.rb:493:in `call'
  warden (0.10.7) lib/warden/manager.rb:35:in `block in call'
  warden (0.10.7) lib/warden/manager.rb:34:in `catch'
  warden (0.10.7) lib/warden/manager.rb:34:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/best_standards_support.rb:17:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/head.rb:14:in `call'
  rack (1.2.4) lib/rack/methodoverride.rb:24:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/params_parser.rb:21:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/flash.rb:182:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/session/abstract_store.rb:149:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/cookies.rb:302:in `call'
  activerecord (3.0.7) lib/active_record/query_cache.rb:32:in `block in call'
  activerecord (3.0.7) lib/active_record/connection_adapters/abstract/query_cache.rb:28:in `cache'
  activerecord (3.0.7) lib/active_record/query_cache.rb:12:in `cache'
  activerecord (3.0.7) lib/active_record/query_cache.rb:31:in `call'
  activerecord (3.0.7) lib/active_record/connection_adapters/abstract/connection_pool.rb:354:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/callbacks.rb:46:in `block in call'
  activesupport (3.0.7) lib/active_support/callbacks.rb:416:in `_run_call_callbacks'
  actionpack (3.0.7) lib/action_dispatch/middleware/callbacks.rb:44:in `call'
  rack (1.2.4) lib/rack/sendfile.rb:106:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/remote_ip.rb:48:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/show_exceptions.rb:47:in `call'
  railties (3.0.7) lib/rails/rack/logger.rb:13:in `call'
  rack (1.2.4) lib/rack/runtime.rb:17:in `call'
  activesupport (3.0.7) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
  rack (1.2.4) lib/rack/lock.rb:11:in `block in call'
  &lt;internal:prelude&gt;:10:in `synchronize'
  rack (1.2.4) lib/rack/lock.rb:11:in `call'
  actionpack (3.0.7) lib/action_dispatch/middleware/static.rb:30:in `call'
  railties (3.0.7) lib/rails/application.rb:168:in `call'
  railties (3.0.7) lib/rails/application.rb:77:in `method_missing'
  railties (3.0.7) lib/rails/rack/log_tailer.rb:14:in `call'
  rack (1.2.4) lib/rack/content_length.rb:13:in `call'
  rack (1.2.4) lib/rack/handler/webrick.rb:52:in `service'
  /home/peanut/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/webrick/httpserver.rb:111:in `service'
  /home/peanut/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/webrick/httpserver.rb:70:in `run'
  /home/peanut/.rvm/rubies/ruby-1.9.2-p180/lib/ruby/1.9.1/webrick/server.rb:183:in `block in start_thread'
  </code></pre>