Merge pull request #220 from ruijunhuang2010/master

Merge pull request #11 from ChrisBoesch/master
Merge pull request #221 from ruijunhuang2010/master

country default selection for challenge creation
Merge pull request #4 from ChrisBoesch/master

update
Color coding issue resolved
Merge pull request #222 from LI-HE/master

Color coding issue resolved
Merge pull request #12 from ChrisBoesch/master

update