Ruby on Rails初心者必見。Railsでのデバッグの味方byebug（バイバグ）。

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
  # Adds support for Capybara system testing and selenium driver
  gem 'capybara', '~> 2.13'
  gem 'selenium-webdriver'
end

gem 'byebug'

bundle install

# POST /users
  # POST /users.json
  def create
    byebug
    @user = User.new(user_params)

    respond_to do |format|
      if @user.save
        format.html { redirect_to @user, notice: 'User was successfully created.' }
        format.json { render :show, status: :created, location: @user }
      else
        format.html { render :new }
        format.json { render json: @user.errors, status: :unprocessable_entity }
      end
    end
  end

23, 32] in /Users/admin/Rails/sample/app/controllers/users_controller.rb
   23:
   24:   # POST /users
   25:   # POST /users.json
   26:   def create
   27:     byebug
=> 28:     @user = User.new(user_params)
   29:
   30:     respond_to do |format|
   31:       if @user.save
   32:         format.html { redirect_to @user, notice: 'User was successfully created.' }
(byebug)

[25, 34] in /Users/admin/Rails/sample/app/controllers/users_controller.rb
   25:   # POST /users.json
   26:   def create
   27:     byebug
   28:     @user = User.new(user_params)
   29:
=> 30:     respond_to do |format|
   31:       if @user.save
   32:         format.html { redirect_to @user, notice: 'User was successfully created.' }
   33:         format.json { render :show, status: :created, location: @user }
   34:       else
(byebug)

(byebug) @user
#<User id: nil, name: "Foo", age: 40, sex: 1, created_at: nil, updated_at: nil&amp;gt;