func (m MongoDb) User(username string) (user models.User, e error) {
	c := m.Connect(models.COLL_NAME_USER)
	defer m.Close(c)
	err := c.Find(bson.M{"username": username}).One(&user)
	if err != nil {
		return user, ErrMissingUser
	}
	return user, nil
}
func (m MongoDb) User(username string) (user models.User, e error) {
	c := m.Connect(models.COLL_NAME_USER)
	defer m.Close(c)
	err := c.Find(bson.M{"username": username}).One(&user)
	if err != nil {
		return user, ErrMissingUser
	}
	return user, nil
}
// User returns the user with the given username. Error is set to
// ErrMissingUser if user is not found.