big refactoring which also introduces Elo model

* Only one nampespace is used (geography) instead of three
  previously used namespaces (core, accounts, questions).

* Redundant data from database has been removed or moved
  to special tables (skills and difficulties for Elo).

* A lot of things has been removed but should be added in the future
  (commands).

issues: #12, #13
post deploy hook for openshift