title: rake db:migrate Could not connect to server error
body: <p>Hey I want to see someone example app. So I downloaded it off github and installed the version of ruby they are using ruby 2.0.0 but when I try to do <code>$ rake db:migrate</code> I get this error:</p>
  
  <pre><code>rake db:migrate
  rake aborted!
  could not connect to server: Connection refused
      Is the server running on host "localhost" (127.0.0.1) and accepting
      TCP/IP connections on port 5432?
  
  /home/alain/.rvm/gems/ruby-2.0.0-preview2/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:796:in `initialize'
  /home/alain/.rvm/gems/ruby-2.0.0-preview2/gems/activerecord-4.0.0.rc1/lib/active_record/connection_adapters/postgresql_adapter.rb:796:in `new'
  ...(etc)
  </code></pre>
  
  <p>Any idea what I should do ?</p>
  
  <p><strong>database.yml</strong></p>
  
  <pre><code>development:
    adapter: postgresql
    host: localhost
    encoding: unicode
    database: rentmybike_dev
    pool: 5
    username: alain
    password: obama
  
  test:
    adapter: postgresql
    encoding: unicode
    database: rentmybike_test
    pool: 5
  
  # Add the below...
  
  production:
    adapter: postgresql
    host: localhost
    encoding: unicode
    database: rentmybike_production
    pool: 5
    username: alain
    password: obama
  </code></pre>