Add isort & flake8 settings.

setup.cfg

@@ -3,3 +3,17 @@ test = pytest
 
 [wheel]
 universal = 1
+
+[flake8]
+ignore = E501
+max-line-length = 100
+
+[isort]
+known_django = django
+sections = FUTURE,STDLIB,THIRDPARTY,DJANGO,FIRSTPARTY,LOCALFOLDER
+default_section = THIRDPARTY
+known_standard_library = factory,mock,requests
+known_first_party = rest_framework_json_api
+multi_line_output = 3
+line_length = 100
+indent = 4