first commit
Fix files problems
Merge branch 'develop' into aurel
add class Group & Database
Add Test, Improve Group, Database
Merge branch 'aurel' into develop
Clean files
Merge remote-tracking branch 'origin/develop' into David
Merge branch 'develop' into David
change user.cs
change user.cs
Merge branch 'David' into develop
add network and some graphical interface
add network and some graphical interface