Rails associations cache their values.
user.comments # will cache its value
c = Comment.new(:user => user)
user.comments.size #(still returns 0)
many have seen the "force reload" trick
user.comments(true) # forces a load from the database
What if I want to make sure the next call to the association loads from the db?
user.comments.reset # this clears the "loaded" flag so next time it will be reloaded.