Added custom parameters to devise parameter_sanitizer. Closes #767.
Merge branch 'develop'

* develop: (35 commits)
  ALM-653 remove dependencies from retrieval_histories table, use status model for email reports
  ALM-625 use configuration settings for status API host
  ALM-625 make type optional in DOI import
  ALM-625 small formatting change of documentation
  ALM-6125 added example of DOI import rake task
  ALM-625 updated documentation to explain CrossRef import rake task
  ALM-625 fixed test
  ALM-625 use update-date instead of index-date for CrossRef import
  ALM-681 use status code 404 when resolving DOI to incorrect page
  ALM-625 handle ActiveRecord::RecordNotUnique errors when importing articles
  ALM-681 only store canonical_url that contains at least one number
  ALM-625 fix small error in expire_cache
  ALM-625 update status cache after importing articles
  ALM-625 trigger article import
  ALM-625 temporarily disable background jobs
  ALM-625 added tests for import rake tasks
  ALM-625 show number of articles to import in rake task
  ALM-625 run article import in the background
  ALM-625 make offset and rows local variables
  ALM-625 crossref_import.rb is no longer needed
  ...
ALM-625 use underscore instead of hyphen for ENV variables
ALM-625 catch ActiceRecord error if DOI already exists
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.