Enable bundler caching in travis
check if asm maxgrade exists
Merge pull request #245 from wangqiang1208/bugfixing/achievement-nil-asm-maxgrade

Fix assessment max grade nil bug
Bugfix for html editor
Fix aesthetics after being hound-ed
change first to limit in survey controller, thus it will not reulst in an array
Merge pull request #247 from wangqiang1208/bugfixing/survey-summary-answer-order

Fix undefined method `order'  in surveys
Merge pull request #246 from kxmbrian/html_editor_fix

Bugfix for html editor
disable image button when there is no imageuploader
remove html_editor partial
Merge pull request #248 from wangqiang1208/bugfixing/disable-iamge-achievement-html-editor

Disable image button in achievement html editor
Merge pull request #244 from jsyeo/jsyeo-travis-cache

Enable bundler caching in travis
change can_start policy, if a student has ever started, let him start
refine code
Merge pull request #249 from wangqiang1208/features/mission-attempt-auth

if a student has ever started, let him start