add tests on django 1.11 on gitlab CI

.gitlab-ci.yml

@@ -23,6 +23,30 @@ stages:
     extends: ".test"
     image: "python:3.8"
 
+python-2.7-django-1.11-test:
+    extends: ".test"
+    image: "python:2.7"
+    variables:
+      DJANGO_VERSION: '1.11'
+
+python-3.6-django-1.11-test:
+    extends: ".test"
+    image: "python:3.6"
+    variables:
+      DJANGO_VERSION: '1.11'
+
+python-3.7-django-1.11-test:
+    extends: ".test"
+    image: "python:3.7"
+    variables:
+      DJANGO_VERSION: '1.11'
+
+python-3.8-django-1.11-test:
+    extends: ".test"
+    image: "python:3.8"
+    variables:
+      DJANGO_VERSION: '1.11'
+
 python-3.6-django-2.2-test:
     extends: ".test"
     image: "python:3.6"