v0.5.0 not working with auth

[trenpixster]

I believe v0.5.0 broke the auth/3 request:

iex(13)>  Mongo.Db.auth(db,"redacted-username", "redacted-password")
** (ArgumentError) argument error
    :erlang.byte_size(%Mongo.Db{auth: {"redacted-username", "redacted-hash"}, mongo: %Mongo.Server{host: 'redacted.server-hostname.com', id_prefix: 28673, mode: :passive, opts: %{}, port: 10026, socket: #Port<0.5573>, timeout: 6000}, name: "redacted_database_name", opts: %{mode: :passive, timeout: 6000}})
    lib/mongo_request.ex:41: Mongo.Request.cmd/3
    lib/mongo_db.ex:44: Mongo.Db.auth/1

[hieuht817]

I meet the same problem. Please check for me.

[adrianmarino]

Same problem.