Fix audience URL

Dependencies

• [2] 36ZTCZ4F Add basic Persona support
• [3] 2CZSW5S5 Don't redirect to /login if authentication is required
• [4] XJRJ4J7M Add user registration

Change contents

• replacement in src/lib/Hydra/Controller/User.pm at line 78
  [2.392]→[2.392:439](∅→∅)
  − audience => "http://localhost:3000/"
  [2.392]

  [2.439]
  + audience => $c->uri_for('/')