Define `Dish::Plate#key=(value)`
Add `Dish::Plate#methods`
Update plate.rb
Merge branch 'master' of https://github.com/lassebunk/dish into keys
Update dish_test.rb
Merge branch 'pr/5'

Conflicts:
	lib/dish/plate.rb
	test/dish_test.rb
Separate test for setting values
Test methods