blog_rails_api_auth_pt_1_11.rb

# app/services/sign_up_user.rb

def sign_up_user
  user.tap do |user|
    user.reset_token!
    user.save! # raise error if validation fails
  end
end

# app/controllers/v1/users_controller.rb

def create
  user = SignUpUser.perform(user_params)
  render json: user, serializer: AuthenticationSerializer, root: :user
end

# app/controllers/application_controller.rb

class ApplicationController < ActionController::Base
  # ...

  rescue_from ActiveRecord::RecordInvalid do |exception|
    render json: { errors: exception.message }, status: :unprocessable_entity
  end
end