Fixed the struct method pinning; changed from (u User) to (u *User)
Added function Jsonify.

Convenience function for quickly encoding a value as JSON, and writing
it out to a http.ResponseWriter.
Added comments above handler functions.
Teeny-tiny fix-up; set the user.Enabled field to false
POST /api/users/{userId}/activate
Fixed an incorrect string formatting directive: %s -> %d
Added Session.User field.

It is an mgo.DBRef to the user that owns the session.
Added convenience function to pre-parse the Authorization request header
Created RequiresAuth wrapper type.

It also satisfies the http.Handler interface.