removing conditional and working with provided callbacks

user_creation_callbacks.rb

class UsersController < ApplicationController
  def create
    @user_creation = UserCreation.new(self)

    @user_creation.on_success { redirect_to users_path }
    @user_creation.on_failure { render :new }

    @user_creation.please_create_an_user_as_admin(params[:user])
  end
end

# This could be provided through a block, adding a bit of syntactic sugar:

@user_creation = UserCreation.new(self) do
  on_success { redirect_to users_path }
  on_failure { render :new }
end

user_creation_conditionals.rb

class UsersController < ApplicationController
  def create
    user = UserCreation.new(self)
    user_created = user.create_an_user_as_admin(params[:user])

    if user_created
      redirect_to users_path
    else
      @user = user.to_active_record
      render :new
    end
  end
end

# obs.: the .to_active_record is here just to represent the idea that
# we usually send the AR object to the view