Add support for Django CockroachDB driver

As per #509 adds support for Django CockroachDB

environ/environ.py

@@ -115,6 +115,7 @@ class Env:
         'psql': DJANGO_POSTGRES,
         'pgsql': DJANGO_POSTGRES,
         'postgis': 'django.contrib.gis.db.backends.postgis',
+        'cockroachdb': 'django_cockroachdb',
         'mysql': 'django.db.backends.mysql',
         'mysql2': 'django.db.backends.mysql',
         'mysql-connector': 'mysql.connector.django',

tests/test_db.py

@@ -59,6 +59,14 @@
          '',
          ''
          ),
+        # cockroachdb://username:[email protected]:26258/dbname
+        ('cockroachdb://username:[email protected]:26258/dbname',
+         'django_cockroachdb',
+         'dbname',
+         'test.example.com',
+         'username',
+         'secret',
+         26258),
         # mysqlgis://user:password@host:port/dbname
         ('mysqlgis://enigma:[email protected]:5431/dbname',
          'django.contrib.gis.db.backends.mysql',
@@ -156,6 +164,7 @@
         'postgis',
         'postgres_cluster',
         'postgres_no_ports',
+        'cockroachdb',
         'mysqlgis',
         'cleardb',
         'mysql_no_password',