Run iSort in CI

Author: asherf

.travis.yml

@@ -37,6 +37,7 @@ install:
 script:
   - if [[ $TRAVIS_PYTHON_VERSION == "3.7" ]]; then black --check django_prometheus/; fi
   - flake8 django_prometheus
+  - isort -rc django_prometheus/ 
   - coverage run --source=django_prometheus setup.py test
   - python setup.py sdist bdist_wheel
   - pushd  django_prometheus/tests/end2end && PYTHONPATH=../../.. coverage run --source=django_prometheus manage.py test &&  popd

requirements.txt

@@ -2,6 +2,7 @@ Django>=1.11
 django-redis>=4.8
 black; python_version >= '3.6'
 flake8
+isort
 prometheus-client>=0.7
 pip-prometheus>=1.2.1
 mock

tox.ini

@@ -1,2 +1,8 @@
 [flake8]
 ignore = E501,W503
+
+[isort]
+multi_line_output=3
+line_length=88
+force_grid_wrap=0
+include_trailing_comma=True