title: Generate Rails models with mandatory/required fields (i.e not null) from command line
body: <p>Can anyone please help with generating Rails models with mandatory fields/columns (i.e. NOT NULL)? For example,</p>
  
  <pre><code>$rails generate model Role name:string &lt;???&gt;
  </code></pre>
  
  <p>What do I need to specify in order to get the "null: false" constraint as shown below?</p>
  
  <pre><code>class CreateRoles &lt; ActiveRecord::Migration
    def change
      create_table :roles do |t|
        **t.string :name, null: false**
  
        t.timestamps
      end
    end
  end
  </code></pre>
  
  <p>Thanks heaps in advance</p>