Transform SCSS to SASS
Refactor and enhance red mine activity job

* support associations between users and projects
* support user's email
* support user's gravatar
* only send projects with more than one activity
Enhance redmine project widget

* Enlarge widget
* Show user avatars on hover
Prefer User#add_project over exposing projects var.
Don't expose ActivityHolder#activities.
Delegate to private reader actually.
Merge pull request #4 from neopoly/feature-project_user_avatars

Refactors redmine activity job and improves redmine projects widget