Added owner to planting

Previously we got the owner indirectly, through the garden in which the
planting was planted.  Now we're directly specifying an owner.  This
allows us to let people plant things in each other's gardens.

Tests are probably broken at this point; we're about to refactor ALL THE
THINGS.
Refactor ALL THE THINGS

Refactored tests to take into account that plantings now have owners
directly, not via gardens. Mostly this was just tweaking FactoryGirl
calls to do the right thing.
Set planting owner automatically in controller
Added rake task to update planting owner

(using planting.garden.owner)
Added plantings_count (i.e. counter_cache) to Member

Also removed the superfluous .plantings_count method on Crop, which was
causing some confusion.

A thing we learned today: we should use .size to find the size of
ActiveRecord collections, not .count, because .count doesn't use the
cache (while .size does).
Added plantings_count (i.e. counter_cache) to Member

Also removed the superfluous .plantings_count method on Crop, which was
causing some confusion.

A thing we learned today: we should use .size to find the size of
ActiveRecord collections, not .count, because .count doesn't use the
cache (while .size does).
Merge branch 'planting-owner' of github.com:Skud/growstuff into planting-owner
Merge branch 'planting-owner' into dev

Conflicts:
	script/deploy-tasks.sh