Start implementing cookbook show
Implements the cookbook show template
Implement cookbook download controller logic
Add fake ghfmd method
Track cookbook downloads when one of its versions is downloaded
Sketch README extraction
Fix rubocop indentation warning in CookbookVersionsController spec
Remove dead code from CookbookVersion
Seed READMEs along with each seeded cookbook
The cookbook show provides the view with all of its data
Set README content defaults
Extract and save a cookbook's supported platforms
Refactor building supported platforms

The previous approach did not honor the circular validation between
cookbook and cookbook version
Validate platform version constraints
Tighten scope of let in CookbooksController spec
Replace get_version!('latest') with latest_cookbook_version
Document with tests Metadata attribute coercion
Add specs for CookbooksController#show
Test CookbookUpload#finish when the cookbook has no README
Satisfy rubocop by omitting redundant curly-braces