It’s easy, just include the Enumerable module and define an each instance method, which more often than not will just use some other class’s each method. Here’s a really simplified example:
class ATeam
include Enumerable
def initialize(*members)
@members = members
end
def each(&block)
@members.each do |member|
block.call(member)
end
# or
# @members.each(&block)
end
end
ateam = ATeam.new("Face", "B.A. Barracus", "Murdoch", "Hannibal")
#use any Enumerable method from here on
p ateam.map(&:downcase)
For further info, I recommend the following article: Ruby Enumerable Magic: The Basics.
In the context of your question, if what you expose through an accessor already is a collection, you probably don’t need to bother with including Enumerable.