Discuss users UX

I would like to have an ability for users to see their achievements depending on their open-source contribution. This is the biggest motivation for people to do something. So we should have an ability to login into our application through GitHub (in perfect case).

Also, I'm not sure that we should synchronise contributors past... Let's track everything starting from server start.

So I propose the following sync scheme:

* Sync all activity for user starting from server start and calculate all achivements
* Sync all achievements for users no often than in 4 hours (?) (or smarter strategy, depending on user activity?...)
* If user doesn't do anything for 30 days, stop syncing him (to not waste our resources)
* Have _force sync_ button in API

We should also assign points to every achievement and have ranking table...

No files, tests, or entry points are named. Start by locating the server entry point and any existing GitHub integration, then clarify which of login, activity syncing, force sync, achievement points, and ranking is in scope. Done should be defined by an agreed design and acceptance criteria for the selected scope.

Written by the indexing model from the issue text.