Merge branch 'master' into develop

* master:
  ALM-625 catch ActiceRecord error if DOI already exists
  ALM-625 use underscore instead of hyphen for ENV variables
  Added custom parameters to devise parameter_sanitizer. Closes #767.
Create status admin menu item. #79.
Give basic status information to API users. #79.
Give all users access to status API call. #79.
API caching should be done separately for admin/staff users
Stop creating alerts for API authentication errors. Closes #80.
cache_group variable for caching by user category #79
different cache key for status #79.
cache correct rabl object #79.
Use user cache_key based on group #79
Use file cache for troubleshooting #79
simplify caching based on user #79
Open up sources API call to all users #79
Fixed typo.
removed obsolete tests checking for missing API key
Removed middleware that checks for JSON parse errors. Closes #81.
ALM-678 remove default_scope for User class
ALM-678 small tweaks for performance optimization
ALM-678 we always have at least one user when looking at admin panel
ALM-678 fixed typo