auth_controller.rb

class V1::AuthController < V1::BaseController
  skip_before_action :authenticate!

  def create
    @user = User.new(user_params)
    sign_up
  end

  private

  def sign_up
    if @user.save
      render json: { email: @user.email, api_key: @user.generate_api_key }
    else
      render_error
    end
  end

  def render_error
    render_message( 
                   message: "Error in sign up", 
                   info: @user.errors.full_messages, 
                   status: 422   
                  )
  end

  def user_params
    params.require(:user).permit(:email, :password, :password_confirmation)
  end
end