Keeping Controllers Skinny with Service Objects

# app/services/register_patient.rb
class RegisterPatient
  def self.call(**args) = new(**args).call

  def initialize(name:, email:)
    @name = name
    @email = email
  end

  def call
    patient = Patient.create!(name: @name, email: @email)
    WelcomeMailer.with(patient: patient).greeting.deliver_later
    patient
  end
end

# Controller stays a one-liner
def create
  @patient = RegisterPatient.call(name: params[:name], email: params[:email])
  redirect_to @patient
end