start building image upload api
Merge branch 'master' into media-upload

* master:
  Implement standard response schema for all end points
file upload

generally finished.
Merge branch 'media-upload'

* media-upload:
  file upload
  start building image upload api
Merge remote-tracking branch 'upstream/master'

* upstream/master:
  Update error codes
  Add field for survey start date
  Return error if survey not found
Integrate image upload