added simple form and ran bundle install
wrote test for creating new unit
ran the foundation install for the simple form gem
created factory for unit and pound.  added : to 'with'in line 19 of the add new unit test
added resources for units to routes.rb
added actions for index and new to units controller, as well as strong params
added create action to units controller and index page for units
added show page for units and changed redirect after creating a new unit to the show page for the new unit
added validates uniqueness of name to food model
added test for incorrectly adding a new unit
added test for preventing users from adding new units with the same name as old units