This will generate a migration for your application.

Example without columns:

  rake generate:migration name=create_users

db/migrations/<number>_create_users.rb:

  class CreateUsers < ActiveRecord::Migration
    self.up
    end

    self.down
    end
  end

Example with columns:

  rake generate:migration name=create_users cols=username:string,email_address:string,created_at:datetime,updated_at:datetime

db/migrations/<number>_create_users.rb:

  class CreateUsers < ActiveRecord::Migration
    self.up
      create_table :users do |t|
        t.column :username, :string
        t.column :email_address, :string
        t.column :created_at, :datetime
        t.column :updated_at, :datetime
    end

    self.down
      drop_table :users
    end
  end