After running the code in development interactive mode and browsing the plugin setting pages I got the following output:
warn: Route requested but not found: /forum/api/admin/plugins/sso-google?_=1405634045311
warn: Route requested but not found: /forum/api/admin/plugins/sso-google?_=1405634045312
warn: Route requested but not found: /forum/api/admin/plugins/sso-google?_=1405634045313
warn: Route requested but not found: /forum/api/admin/plugins/dbsearch?_=1405634045314
warn: Route requested but not found: /forum/api/admin/plugins/markdown?_=1405634045315
warn: Route requested but not found: /forum/api/admin/plugins/sso-google?_=1405634045316
warn: Route requested but not found: /forum/api/admin/plugins/sso-google?_=1405634045317
warn: Route requested but not found: /forum/api/admin/plugins/markdown?_=1405634045318
warn: Route requested but not found: /forum/api/admin/plugins/dbsearch?_=1405634045319
warn: Route requested but not found: /forum/api/admin/plugins/markdown?_=1405634045320
warn: Route requested but not found: /forum/api/admin/plugins/dbsearch?_=1405634045321
warn: Route requested but not found: /forum/api/admin/plugins/emailer-mailgun?_=1405634045322
warn: Route requested but not found: /forum/api/admin/plugins/dbsearch?_=1405634045323
warn: Route requested but not found: /forum/api/admin/plugins/markdown?_=1405634045324
maybe this would give some more input to the problem and help finding a solution for it.