added csv to application file
added self method to_csv in model and added it into admin controller
merge commit, applied both my changes in view study request
add export to csv
Merge branch 'feature/81-export-requests-to-excel' into staging

* feature/81-export-requests-to-excel:
  add export to csv
  merge commit, applied both my changes in view study request
  added self method to_csv in model and added it into admin controller
  added csv to application file