1. signin with form_tag instead of form_for
9.1.1 Edit form
9.1.2&3 Unsuccessful & successful edits
9.2.1 Requiring signed-in users
9.2.2 Requiring the right user
9.2.3 Friendly forwarding
9.3.1 User index
9.3.2 Sample users
9.3.3 Pagination
9.3.4 Partial refactoring
9.4.1 Administrative users
9.4.2 The destroy action