C2 yomn el mistikawy implement an achievement system #217

@maha-salama @Samarfikri @Nardeen @Sherouk-55 @essama 

Please review my user story

@maha-salama  please before reviewing the test you have to run
1) rake db:migrate RAILS_ENV=test
2) rake db:seed RAILS_ENV=test
3) bundle exec rspec

Thanks 

#217