test 3.7 with postgres and xdist

Author: SalmonMode

.travis.yml

@@ -26,6 +26,8 @@ jobs:
       env: TOXENV=py37-dj21-sqlite-coverage
     - python: 3.7
       env: TOXENV=py37-dj22-sqlite-xdist-coverage
+    - python: 3.7
+      env: TOXENV=py37-dj22-postgres-xdist-coverage
     - python: 3.8
       env: TOXENV=py38-dj30-sqlite-xdist-coverage