Hi Mike and Andy,
Andy is right, when I create a new docker image and copy the user.xml to /srv/BaseXData then I can authenticate with the credentials defined in user.xml. As the passwords are encrypted I just used the DBA webconsole to change the admin password on my local machine and then I can use this file when creating the docker image, i.e. in the Dockerfile I added the following line:
COPY users.xml /srv/BaseXData/
I think it should be clarified in the official documentation: http://docs.basex.org/wiki/Docker#BaseX_Configuration (changing the admin password has no effect...)
I just added some information to the Docker documentation page:
http://docs.basex.org/wiki/Docker
If you have more helpful information to add to he documentation, it is written using a Wiki and everybody's invited to improve it, but you'll have to request an account to prevent spam before:
http://docs.basex.org/wiki/Special:RequestAccount
I'm still investigating an issue together with Docker which prevents the automated builds from automatically adding new releases, but I hope this will be resolved in the next few days.
Regards, Jens