Add missing setup.cfg

.gitignore

@@ -85,4 +85,3 @@ pretalx.cfg
 .DS_Store
 
 .pytest_cache
-*.cfg

setup.cfg

@@ -0,0 +1,40 @@
+[isort]
+multi_line_output=3
+include_trailing_comma=True
+force_grid_wrap=0
+use_parentheses=True
+line_length=88
+known_first_party=pretalx_salesforce
+known_third_party=pretalx
+skip=setup.py
+combine_as_imports=True
+default_section = THIRDPARTY
+
+[tool:pytest]
+DJANGO_SETTINGS_MODULE=pretalx.common.settings.test_settings
+
+[check-manifest]
+ignore =
+  Makefile
+  LICENSE
+  README.rst
+  .gitkeep
+
+[flake8]
+ignore = E203, E231, E266, E501, W503, W605
+max-line-length = 160
+exclude = migrations,static,_static,build,*settings.py,.tox/*,local
+
+[coverage:run]
+branch = True
+source = pretalx_salesforce
+omit = */migrations/*,*/urls.py,*/tests/*
+
+[coverage:report]
+exclude_lines =
+    pragma: no cover
+    def __str__
+    der __repr__
+    if settings.DEBUG
+    NOQA
+    NotImplementedError