GitLab always Redirects to HTTPS

I would like to run GitLab behind an Apache Reverse Proxy. The Apache makes all the SSL Stuff.

I´ve configured gitlab.rb like this.

external_url 'https://gitlab.example.com'
nginx['listen_address'] = '192.168.178.63'
nginx['listen_port'] = 8888
nginx['listen_https'] = false
nginx['external_users'] = ['http']

but when i enter the 192.168.178.63 in my webbrowser Gitlab always redirects me to https://192.168.178.63 but thats wrong the embedded Webserver from gitlab shoud do everithing with HTTP only

The problem is

external_url 'https://gitlab.example.com'

if i change it to

external_url 'http://gitlab.example.com'

everything works fine but it does not solve my problem because now gitlab thinks the external URL is only a HTTP not HTTPS.

How can I kill this redirect to https? That the Gitlab embedded Webserver does everything with http and the reverse proxy the ssl stuff

Thanks.