title: acts-as-taggable-on with simple text input
body: <p>i'm a RoR newbie and i'm trying to create a simple blog platform. Currenty i'm stuck on making a tagging possibility.</p>
  
  <p>I've installed <a href="https://github.com/mbleigh/acts-as-taggable-on" rel="nofollow">acts-as-taggable-on</a> gem, added <code>acts_as_taggable</code> to my <code>post</code> model. Here is my form (based on <a href="https://we.riseup.net/rails/tagging-tutorial" rel="nofollow">this</a> tutorial):</p>
  
  <pre><code>&lt;%= form_for(@post) do |f| %&gt;
    &lt;div class="field"&gt;
      &lt;%= f.label :title %&gt;&lt;br /&gt;
      &lt;%= f.text_field :title %&gt;
    &lt;/div&gt;
    &lt;div class="field"&gt;
      &lt;%= f.label :tag_list %&gt;&lt;br /&gt;
      &lt;%= f.text_field :tags, :tag_list %&gt;
    &lt;/div&gt;
    &lt;div class="actions"&gt;
      &lt;%= f.submit %&gt;
    &lt;/div&gt;
  &lt;% end %&gt;
  </code></pre>
  
  <p>But when i'm trying to point by browser to i.e. <code>edit</code> form, all i get is the following error: </p>
  
  <pre><code>undefined method `merge' for :tag_list:Symbol 
  </code></pre>
  
  <p>Have you any idea what am i doing wrong? It's probably something really simple :) Thanks in advance!</p>