title: Cannot load `Rails.application.database_configuration`: Unknown alias: default
body: <p>I am new to Ruby on Rails and I am guessing that the answer to my question is pretty simple but I can't find it. I recently created a project and used "rails generate scaffold..." and everything was working fine. I wanted to add another column to the database so I used "rails generate migration ...." Everything worked well after this too. The problem started after I stopped the server and restarted it. Now I get this error 
  Psych::BadAlias
  Cannot load <code>Rails.application.database_configuration</code>: Unknown alias: default</p>
  
  <p>I found this <a href="https://stackoverflow.com/questions/23847007/requesting-a-ruby-on-rails-application-gives-psychbadalias-error">Requesting a ruby-on-rails application gives Psych::BadAlias error</a> but I didn't see a definite answer. </p>
  
  <p>Here is what my database.yml file looks like...  </p>
  
  <pre><code>  #  
  
    &lt;&lt;: *default 
      database: db/development.sqlite3 
  
  
    test:
      &lt;&lt;: *default
      database: db/development.sqlite3_test
  
    production:
      &lt;&lt;: *default  
      database: db/development.sqlite3_production 
  </code></pre>
  
  <p>Here is the file that genereated after I did the migration</p>
  
  <pre><code>class AddHardwareToComputers &lt; ActiveRecord::Migration
    def change
      add_column :computers, :hardware, :string
    end
  end
  </code></pre>
  
  <p>and here is my schema.rb</p>
  
  <pre><code>ActiveRecord::Schema.define(version: 20140723203054) do  
  
    create_table "computers", force: true do |t|
      t.string   "name"
      t.string   "serial_number"
      t.string   "user"
      t.datetime "created_at"
      t.datetime "updated_at"
      t.string   "hardware" 
    end
  
  end
  </code></pre>
  
  <p>Any help would be appreciated. Thank you.</p>