enable autocomplete of the "category" value

[vanderhoop]

As a retrospective participant, I would like the ability to autocomplete the "category" input from available categories ("happy", "sad", or "confused"), so that I don't have to type the entirety of the category every time i want to submit an item belonging to a different category.

Acceptance Criteria:

• when a user types either "s", "h", or "c" into the category input, a dropdown of possible autocomplete options appears.
  • Note: because there are only 3 categories in the MVP retro format-- and they start with unique letters--there would only be one option available for any of these three cases.

Libraries to Investigate:

• https://github.com/ianmcnally/react-input-completion/issues
  • written by our own Ian McNally
• https://github.com/reactjs/react-autocomplete
  • autocomplete as written by the ReactJS team

[vanderhoop]

shifting to a select tag, closing