✨ Don't lock Django to explicit version ...

... but rather use the same definition that is currently used in
Netbox's `requirements.txt`.

✏️ Added nginx troubleshooting section

🆙 Update nginx to the latest version

✨ Use a default Redis password ...

Although it does not provide any additional security, it shows how to
configure Redis with a password and how to use Netbox using a password
protected redis server. Something that might be considered in a classic
production deployment. (But is mostly irrelevant in e.g. a Kubernetes /
OpenShift deployment as the isolation is usually on a network level.)

♻️ Make netbox-worker it's own container ...

One container should ideally have one responsibility [1]. Therefore I
implemented the netbox-worker to start in it's own container. This is
possible, because netbox and the worker communicate via redis anyway.

They still use the same image underneath, just the "command" they
execute while starting different.

Or in other words: I see no reason to introduce supervisord, when we
already have docker-compose which can take care of running multiple
processes.

Also, here's another benefit: Now it's possible to view the logs of the
webhook worker independently of the other netbox logs (and vice-versa).

Other changes in this commit:
* I don't see a reason to put a password for Redis in the docker-compose
  setup, so I removed it.
* Slightly changed the nginx config, so that the nginx startup command
  becomes simpler and any error should be visible in the docker log.
* Some housekeeping in the `Dockerfile`.
* Added some troubleshooting advice regarding webhooks to the README.

I'd like to thank Brady (@bdlamprecht [2]) here who did the harder
work of figuring out what's even required to have webhooks working. [3]

[1] 
https://docs.docker.com/develop/develop-images/dockerfile_best-practices/#decouple-applications
[2] https://github.com/bdlamprecht
[3] https://github.com/ninech/netbox-docker/pull/90

✨ Disable webhooks by default* ...

*but enable it by default for anyone who checks out the netbox-docker project
via the netbox.env file.

✨ Read redis password like any other secret

Working implementation of webhooks using new 'redis' container

Bump VERSION file

⚙️ Don't build webhook branch anymore ...

Because it's merged into Netbox since 2.4.

Merge pull request #86 from hex2a/patch-1 ...

✨docker-compose: use latest postgres minor version (10.4)

Merge branch 'master' into patch-1

Merge pull request #83 from GnomeZworc/master ...

Add auth-ldap-user-dn-template in ldap_config.py

Merge branch 'master' into master

Merge pull request #85 from sts/patch-1 ...

Update docker-entrypoint.sh

Merge branch 'master' into master

✨docker-compose: use latest postgres minor version (10.4)

Update docker-entrypoint.sh ...

Make netbox-docker function with  v2.4-beta1 again, fixes #84.

> The shell --plain option is deprecated in favor of -i python or --interface python.
> The shell --interface option now accepts python to force use of the “plain” Python interpreter.
https://docs.djangoproject.com/en/2.0/releases/1.10/#deprecated-features-1-10

Update ldap_config.py

Change default value of AUTH_LDAP_USER_DN_TEMPLATE

Merge pull request #82 from DisasteR/fix-bad-ldap-variable ...

resolve AUTH_LDAP_GROUP_CACHE_TIMEOUT from env

Add auth-ldap-user-dn-template in ldap_config.py

resolve AUTH_LDAP_GROUP_CACHE_TIMEOUT from env ...

Resolve ValueError: invalid literal for int() for AUTH_LDAP_GROUP_CACHE_TIMEOUT

Merge pull request #80 from ninech/fix-79 ...

Import Error Fix

use docker-compose.yml instead of docker-compose.test.yml

add initializers to specs

fix import constant

fix deprecated value

Merge pull request #55 from Grokzen/auto_weight_choices ...

Add support for auto_weight counter

Merge branch 'master' into auto_weight_choices