To be included by classes that generate avatar URLs from profiles.
Return an avatar URL for the person, or nil if this source cannot generate
one. Including classes must override this method. In general,
implementations should return nil if person
is nil.
# File lib/avatar/source/abstract_source.rb, line 9 def avatar_url_for(person, options = {}) raise NotImplementedError.new('including class must define avatar_url_for(person, options = {})') end