Ask HN: How to Open Source an already live project?

I am one of the founders of a crowd funded Go(game) Server and currently both me and my partner have day jobs and can't put in the development time we used to to improve the project.

It has thousands of registrations and although there is a lot to improve, there is also a lot of work done. It has thousands of games played a month and if it were to continue improve it could surpass current alternative Go Servers.

One idea to help the project improve is to Open source it, and us founders can become code controllers (plus maintainers and occasional fixers/improvers as we are now). If we could build a community around technical collaboration it could vastly improve.

Kaya has an OpenKaya project on github, and several libraries and functionalities were done in collaboration with other users (We have open sourced tools and parts of the application that we deemed reusable in other places).

However, the majority rest of the code is not a general solution re-applicable for other purposes than a Go Server, so collaboration would be mostly be applicable to the project itself.

For sure, open-sourcing the code cowboy style will not work. We want to build community around it, and be prepared for this potential change. How to face it?

How to build a developer contributor community around the project?

What should we look out for if we open source it?

What are the guidelines for an open source maintainer?

What could we learn from Firefox, or Diaspora for specific project collaborations (as opposed to gems or libraries that can be reused for different purposes)