Add badge helper for counts.
Add status scopes for Approval and BorrowRequest
Add badge counts for requests awaiting approval, approved requests, rejected requests and pending requests
Force DB check on BorrowRequest status scopes
Correct comment on BorrowRequest.request_pending?
Add belongs_to association between Transfer and BorrowRequest
Add comments about system design
Add has_one association from BorrowRequest to Transfers
Add "transferred" as possible BorrowRequest status

Defined as approved requests with a referencing Transfer record.
Reimplement BorrowRequest.request_pending to not break on approval undo
Remove resolved todo
Remove unnecessary todo
Refactor to expose pending requests for use in views
Add pending request information to Thing view
Remove tags placeholder
Decrease prominence of headings in borrow request and thing partials
Switch approval and rejection links to use thumbs up/down instead of check/x
Change signed in root route to borrow requests index
Fix issue where redundant requests would appear in pending request count.
Change button text from "Ask to Borrow" to just "Borrow"