Remove postgress dependencies to allow valid Docker build.

requirements.txt

 Django==1.11.3
 mysqlclient
-postgresql
-postgresql-contrib
-psycopg2
+#postgresql
+#postgresql-contrib
+#psycopg2
 Pillow==4.2.1
 PyYAML==3.12
 django-tinymce==2.6.0
@@ -11,4 +11,4 @@ django-versatileimagefield==1.8.1
 djangorestframework==3.7.3
 drf-nested-routers==0.90.0
 django-oidc-provider==0.5.2
-django-cors-headers
\ No newline at end of file
+django-cors-headers