title: Error while running the ruby server says connection not established
body: <p>I am using rails 3.2.9 and database of postgres.</p>
  <p>I have edited database.yml file in the following way and also <code>gem pg</code> was also installed..</p>
  <p>When I run bundle command it shows pg gem in that list. But if I run the rails server command it shows the active connection not established.</p>
  <pre><code>    development:
        adapter: postgresql
        database: db_pchamara/development.postgresql
        pool: 5
        username: database username
        password: password
        host: database ip address
      
      test:
        adapter: postgresql
        database: database name/test.postgresql
        pool: 5
        username:database username
        password: password
      
      production:
        adapter: postgresql
        database: database name/production.postgresql
        pool: 5
        username: database username
        password: password
  </code></pre>
  <p>But when I run command <code>rails server</code> it shows as follows:</p>
  <pre><code>[root@vdimc04 my_app]# rails server
  =&gt; Booting WEBrick
  =&gt; Rails 3.2.9 application starting in development on http
  =&gt; Call with -d to detach
  =&gt; Ctrl-C to shutdown server
  [2012-12-06 12:49:35] INFO  WEBrick 1.3.1
  [2012-12-06 12:49:35] INFO  ruby 1.9.3 (2012-11-10) [i686-linux]
  [2012-12-06 12:49:35] INFO  WEBrick::HTTPServer#start: pid=7536 port=3000
  
  
  Started GET &quot;/assets/rails.png&quot; for 127.0.0.1 at 2012-12-06 12:49:53 +0530
  
  ActiveRecord::ConnectionNotEstablished (ActiveRecord::ConnectionNotEstablished):
    activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_pool.rb:410:in `retrieve_connection'
    activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_specification.rb:171:in `retrieve_connection'
    activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_specification.rb:145:in `connection'
    activerecord (3.2.9) lib/active_record/query_cache.rb:67:in `rescue in call'
    activerecord (3.2.9) lib/active_record/query_cache.rb:61:in `call'
    activerecord (3.2.9) lib/active_record/connection_adapters/abstract/connection_pool.rb:479:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/callbacks.rb:28:in `block in call'
    activesupport (3.2.9) lib/active_support/callbacks.rb:405:in `_run__626989987__call__446659449__callbacks'
    activesupport (3.2.9) lib/active_support/callbacks.rb:405:in `__run_callback'
    activesupport (3.2.9) lib/active_support/callbacks.rb:385:in `_run_call_callbacks'
    activesupport (3.2.9) lib/active_support/callbacks.rb:81:in `run_callbacks'
    actionpack (3.2.9) lib/action_dispatch/middleware/callbacks.rb:27:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/reloader.rb:65:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/remote_ip.rb:31:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/debug_exceptions.rb:16:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/show_exceptions.rb:56:in `call'
    railties (3.2.9) lib/rails/rack/logger.rb:32:in `call_app'
    railties (3.2.9) lib/rails/rack/logger.rb:16:in `block in call'
    activesupport (3.2.9) lib/active_support/tagged_logging.rb:22:in `tagged'
    railties (3.2.9) lib/rails/rack/logger.rb:16:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/request_id.rb:22:in `call'
    rack (1.4.1) lib/rack/methodoverride.rb:21:in `call'
    rack (1.4.1) lib/rack/runtime.rb:17:in `call'
    activesupport (3.2.9) lib/active_support/cache/strategy/local_cache.rb:72:in `call'
    rack (1.4.1) lib/rack/lock.rb:15:in `call'
    actionpack (3.2.9) lib/action_dispatch/middleware/static.rb:62:in `call'
    railties (3.2.9) lib/rails/engine.rb:479:in `call'
    railties (3.2.9) lib/rails/application.rb:223:in `call'
    rack (1.4.1) lib/rack/content_length.rb:14:in `call'
    railties (3.2.9) lib/rails/rack/log_tailer.rb:17:in `call'
    rack (1.4.1) lib/rack/handler/webrick.rb:59:in `service'
    /usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/webrick/httpserver.rb:138:in `service'
    /usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/webrick/httpserver.rb:94:in `run'
    /usr/local/rvm/rubies/ruby-1.9.3-p327/lib/ruby/1.9.1/webrick/server.rb:191:in `block in start_thread'
  
  
    Rendered /usr/local/rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/templates/rescues/_trace.erb (1.3ms)
    Rendered /usr/local/rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/templates/rescues/_request_and_response.erb (3.0ms)
    Rendered /usr/local/rvm/gems/ruby-1.9.3-p327/gems/actionpack-3.2.9/lib/action_dispatch/middleware/templates/rescues/diagnostics.erb within rescues/layout (29.4ms)
  </code></pre>
  <pre><code>    
  Please help me to solve this problem.
  </code></pre>