Extending Rails models

Question

Rails models come with certain built-in methods like this:

Appointment.new
Appointment.find(1)

How do I add more methods to Appointment? It's apparently not done by adding methods to app/models/appointment.rb. Doing that adds methods to an instance of Appointment, but I want to add methods to Appointment itself. How do I do that?

Answer 1

def self.some_method
  #do stuff
end