Add OWNCLOUD_TRUSTED_DOMAINS to the Docker example

[michaelstingl]

Needed because of this change: owncloud-docker/server#340

Description

Add OWNCLOUD_TRUSTED_DOMAINS to the Docker example

Related Issue

owncloud-docker/server#340

Motivation and Context

Change in the ownCloud Docker now require to configure the trusted domains

How Has This Been Tested?

Run:

docker run --rm -d \
  --name owncloud \
  -p 18080:8080 \
  -e OWNCLOUD_TRUSTED_DOMAINS=192.168.68.64 \
  -e OWNCLOUD_APPS_ENABLE=oauth2 \
  -e ADMIN_USERNAME=admin \
  -e ADMIN_PASSWORD=admin \
  owncloud/server:latest

Then check if it works with browser:
http://192.168.68.64:18080/login

Screenshots (if appropriate):

Types of changes

• Bug fix (non-breaking change which fixes an issue)
• New feature (non-breaking change which adds functionality)
• Breaking change (fix or feature that would cause existing functionality to change)

Checklist:

• My code follows the code style of this project.
• My change requires a change to the documentation.
• Added an issue with details about all relevant changes in the iOS documentation repository.
• I have read the CONTRIBUTING document.
• I have added tests to cover my changes.
• All new and existing tests passed.
• Added changelog files for the fixed issues in folder changelog/unreleased

[hosy]

Does it make sense to add that 192.168.68.64 is a sample IP address and needs to be adopted to the own local network?

[michaelstingl]

@hosy propose a change? Add "(example)" to make it more clear?