class CreateRoles < ActiveRecord::Migration[4.2] def self.up create_table :roles, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci" do |t| t.column 'name', :string end create_table :roles_users, :id => false, options: "ENGINE=InnoDB DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci" do |t| t.column 'role_id', :integer t.column 'user_id', :integer end add_index :roles_users, :user_id end def self.down drop_table :roles_users drop_table :roles end end