Investigate a pattern for #destroy actions.

[richardkmichael]

• Is there a Rails pattern for handling these redirects?
• What to do when the item to be destroyed can't be found?
• What to do after the destroy, e.g. where to redirect?
• Should we render(), and not redirect() - why round-trip the browser? See: (Builds|Projects)Controller#destroy

app/controllers/builds_controller.rb
If no @build, root_path; else, project_path(@build.project).