rails devise plugin has created a users table. How can I add to it?

I created the following with the devise rails plugin. How do I go about adding a username string and unique user_id integer to the users table? Also is it necessary to create a users_controller when using devise? Or is that not necessary?

class DeviseCreateUsers < ActiveRecord::Migration
  def self.up
    create_table(:users) do |t|
      t.database_authenticatable :null => false
      t.recoverable
      t.rememberable
      t.trackable

      # t.encryptable
      # t.confirmable
      # t.lockable :lock开发者_开发技巧_strategy => :failed_attempts, :unlock_strategy => :both
      # t.token_authenticatable


      t.timestamps
    end

    add_index :users, :email,                :unique => true
    add_index :users, :reset_password_token, :unique => true
    # add_index :users, :confirmation_token,   :unique => true
    # add_index :users, :unlock_token,         :unique => true
    # add_index :users, :authentication_token, :unique => true
  end

  def self.down
    drop_table :users
  end
end

The guide linked to in the comments will provide good reading on migrations, which you will come to use very frequently. In short, however, you can generate the migration needed by doing:

rails g migration add_username_to_users username:string

Once the migration is created, you can actually add the column by doing:

rake db:migrate

To answer to your last question, no, you don't need to create a controller to use devise

Although you could do if you wanted to have an index or show page for your users. In which case you would need to modify your routes a little