User Story 59, Merchant sees an order show page

[iandouglas]

As a merchant
When I visit an order show page from my dashboard
I see the customer's name and address
I only the items in the order that are being purchased from my inventory
I do not see any items in the order being purchased from other merchants
For each item, I see the following information:
- the name of the item, which is a link to my item's show page
- a small thumbnail of the item
- my price for the item
- the quantity the user wants to purchase

Checklist:

• base code 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 reviewed
• branch is merged
• all tests still pass

child of #8

depends on #30