User Show Page

[turing-cardcannon]

As a Visitor,
When I click on a user's name for any book review
I am taken to a show page for that user.
I should see all reviews (title, rating and text) that this
user has written.

Checklist:

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

child of #14

depends on #18