create_hookup

PT#: 75024892
Added a form on the hookups/index view for creating a new hookup (e.g. remote pair programming event)
This form can be shown/hidden with control by a button using javascript.
Javascript is tested via Cucumber features.
the `if` can be inlined here, and also a couple of lines later you are using another `if` with the `start_date` param, I would suggest assigning a `start_date` here which you can use later on without the extra `if` statement, something like:

~~~ruby
start_date = params[:event_date] ? params[:event_date].to_datetime.strftime('%F') : Time.now.utc
~~~

and do the same for `start_time` :grinning: