Special for external database Servers

Base: https://github.com/Gronis/docker-seafile
Adjusted with help of: https://github.com/eplightning/seafile-kubernetes

This docker image is not related to Seafile Ltd. in any way.
It is a private contribution to use Seafile Pro with an external database server.
When you use it, you agree to the Seafile Pro license and provide a license file.
Information: https://www.seafile.com/en/product/private_server/