Added navigation menu in top of layout

Reference:
http://railsapps.github.io/rails-default-application-layout.html
Added 'Edit User' workflow to menu.
Removed menu link at bottom of edit user since it is in nav bar
Removed Show and disabled Destroy from Users controller
Removed show from Users controller
Changed flash on Users destroy to alert (red) instead of notice (green)
Working on Expense add form
Finished expense new test with valid attributes