Install bootstrap-datepicker-rails Gem.
Allow free-form input of dates in plantings form.

See http://railscasts.com/episodes/32-time-in-text-field?view=asciicast

If an existing date has been set, it's pre-filled in ISO format.
Tried to use Bootstrap datepicker. Failed!

We get the Javascript error "datepicker is not a function".
Create new plantings with planted_at set to today.

There may be issues with time zones: can someone not on UTC test this?
fixed pozorvlak's date-picker branch

- tweaked javascript to specify date format (this fixed the javascript
    problems)
- converted planted_at to a date field, rather than datetime
- made tests pass even in non-UTC timezones
Merge pull request #148 from Skud/date-picker

Date picker