slowsword

I have searched for this for a while now and have not found what I was looking for (if something like this even exists). Is there an SDK of some sort or a package program that would basically give a place on a server for a database and a membership system that is easily integrated into a android app I am developing? Something that would connect the users in my app like they do in instagram, or words with friends, or pretty much any other multiplayer game. (i am not looking for a facebook connect, or a twitter connect. just something that connects just my app together so to speak)

Any information or help would be greatly appreciated.

Thanks