Add instructions for installing and using HLint
Merge pull request #1462 from soapie/master

Add instructions for installing and using HLint
Upgrade puma
Upgrade activerecord
Update redcarpet
Upgrade pony
Upgrade newrelic_rpm
Upgrade sqlite3
Upgrade approvals
Suggest go fmt in golang setup. See #1461
Tweak error message in API
Protect against unknown exercises
Update approvals
Working with RubyMine
Marking a user exercise as needing input
Add dropdown for users whose identity you can assume (for development only)
Merge pull request #1467 from michaelavila/assume_identity_in_development

Add dropdown for users whose identity you can assume (for development on...
Menu item for needs-input
Replacing and with &&
Returning submissions that needs input