when the app is mounted we cannot log to the vue logger yet
this throws an error before the signOut method is called

now fixed by using console.log only in debug environments

fixes #5

vue always throws a render error, even if we include a test for user.steeringUser
before comparing user.steeringUser.is_superuser.

so we moved it to the js logic and use a separat modules array for superusers

For vue-devtools see https://github.com/vuejs/vue-devtools

* deactivate superuser entries for standard users
* consistent naming

we don't need to show the method name as it will only
always show the es6 node core module of node an not
the actual method in our vue application.