Prepare 0.9.0

This change is in accordance with https://github.com/digitalocean/netbox/issues/2808

Dockerfile

@@ -25,7 +25,7 @@ RUN pip install \
 # pinning django to the version required by netbox
 # adding it here, to install the correct version of
 # django-rq
-      'Django>=1.11,<2.1' \
+      'Django>=2.1.5,<2.2' \
 # django-rq is used for webhooks
       django-rq
 

README.md

@@ -378,6 +378,7 @@ Compare the version with the list below to check whether a breaking change was i
 
 The following is a list of breaking changes of the `netbox-docker` project:
 
+* 0.9.0: Upgrade to at least 2.1.5
 * 0.8.0: Alpine linux was upgraded to 3.9 [#126][126]
 * 0.7.0: The value of the `MAX_PAGE_SIZE` environment variable was changed to `1000`, which is the default of Netbox.
 * 0.6.0: The naming of the default startup_scripts were changed.