title: Option for Cascade Delete for References or On Delete
body: <p>In Rails 4.2, when creating a table or adding a reference via references or add_reference how do you specify that the foreign key should cascade on delete.</p>
  
  <p>Command to generate scaffold:</p>
  
  <pre><code>rails g scaffold Child parent:references name:string
  </code></pre>
  
  <p>Resulting migration:</p>
  
  <pre><code>create_table :childs do |t|
    t.references :parent, index: true, foreign_key: true
    t.string :name
  
    t.timestamps null: false
  end
  </code></pre>