They finally pushed the code out: https://github.com/signalapp/Signal-Server/commits/master
From an open source perspective Signal-Server is still not open and never was: No outside contributions and no public issues. No community. No installation documentation. etc. ... and recently they seem to have added a dependency to DynamoDB: https://github.com/signalapp/Signal-Server/commit/0dcb4b645c... (2 weeks after they were overloaded from user registrations)