Workmate is a project management and collaboration platform. It's used to manage a workflow and communicating in teams. The basic features are simple: Organize discussions within team, assign and track tasks, store notes and files. This is free to use.
The uniqness of platform is that it has an add-on store, where you can find any tool you need for teamwork. For example, now we are working to get to the store a scrum-based task tracker and github integration. Soon we will open our API so that free developers could write their own add-ons, if they can't find an alternative in an Add-on store.