How do I define in the model a class method, not an instance one?

I want to be able to call Activity.pull_latest from a controller, but if I do

class Activity < ActiveRecord::Base
  def pull_latest [...]

I have to call it Activity.new.pull_latest.

How do I define in the model a class method, not an instance one?开发者_运维百科

Use self:

def self.pull_latest

Then you can call Activity.pull_latest