User Story 20, Change Item's Active Status

[megstang]

As a visitor
When I visit an Item Show page
Then I see a link to change the Item's active status
Active items should have the link "deactivate"
Inactive items should have the link "activate"
When I click the link
Then a 'PATCH' request is sent to '/items/:id/activate' or 'items/:id/deactivate' (depending on the link)
and I am redirected to the Item Show page where I see the active status has been toggled

DO THESE STORIES FIRST:

• User Story 9, Item Show

Checklist:

• base tests are written
• base code is written to pass tests
• edge case ("sad path") tests written (if required)
• edge case code written (if required)
• code is tested in development
• code is reviewed
• branch is merged
• all tests still pass

child of turingschool-examples#108

child of turingschool-examples#130

depends on turingschool-examples#119