复选框不使用Rails 4更新数据库

# app/models/user.rb
class User < ActiveRecord::Base
  has_many :user_roles
  has_many :roles, through: :user_roles
end

# app/models/role.rb
class Role < ActiveRecord::Base
  has_many :user_roles
  has_many :users, through: :user_roles
end

# app/models/user_role.rb
class UserRole < ActiveRecord::Base
  belongs_to :user
  belongs_to :role
end

<!-- app/views/users/edit.html.erb -->
<%= form_for @user do |f| %>
  <%= f.label :roles %>
  <%= f.collection_check_boxes :role_ids, Role.all, :id, :name %>
  <%= f.submit "Update" %>
<% end %>

# app/controllers/users_controller.rb
class UsersController < ApplicationController
  before_action :set_user, only: [:edit, :update]

  def edit
  end

  def update
    if @user.update(user_params)
      redirect_to @user, notice: 'User was successfully updated.'
    else
      render :edit
    end
  end

  private

  def set_user
    @user = User.find(params[:id])
  end

  def user_params
    params.require(:user).permit(:name, role_ids: [])
  end
end