Improve reservation length editing
This does two things:
- defaults the reservation length to 1 hour when the length can be selected.
- the saved reservation length is selected by default when editing a reservation (instead of defaulting to the 1st option)
I did this assuming that the select is used mostly for room reservations, which are usually one hour reservations (in my experience).
Also, my ruby-fu is lacking, so there might be a better way to do this?