Can we not just use this search all the time without doing the above search, followed by a second?  The only downside I can think of is if the login field is indexed, the `LOWER(login)` probably won't take advantage.

This would enable this find_* method to be rewritten as a scope, which means we can use it more easily, and it wouldn't force the user to use User.unscoped (which may not always be appropriate).