Update the README to mention Django 2.0 support
Update the README to mention Django 2.0 support

django-treebeard/django-treebeard,tabo/django-treebeard,django-treebeard/django-treebeard,tabo/django-treebeard,tabo/django-treebeard,tabo/django-treebeard,django-treebeard/django-treebeard