PR #5210 added a Friendship model to illustrate a bug, but in doing so
created a confusing structure because both belongs_to declarations in
Friendship referred to the same side of the join. The new structure
maintains the integrity of the bug test while changing the follower
relationship to be more useful for other testing.
With self referential associations, the scope for the the top level should not affect fetching of associations, for example
when doing
Person.male.find :all, :include => :friends
we should load all of the friends for each male, not just the male friends.
