add docstring testing

requirements.txt

@@ -33,6 +33,7 @@ django-weasyprint==1.0.1                # django weasyprint integration
 djangorestframework==3.12.4             # DRF framework
 django-xforwardedfor-middleware==2.0    # IP forwarding metadata
 flake8==3.8.3                           # PEP checking
+flake8-docstrings==1.6.0                # docstring format testing
 gunicorn>=20.1.0                        # Gunicorn web server
 importlib_metadata                      # Backport for importlib.metadata
 inventree                               # Install the latest version of the InvenTree API python library

setup.cfg

@@ -15,8 +15,11 @@ ignore =
 	N806,
 	# - N812 - lowercase imported as non-lowercase
 	N812,
+	# - D415 - First line should end with a period, question mark, or exclamation point
+	D415,
 exclude = .git,__pycache__,*/migrations/*,*/lib/*,*/bin/*,*/media/*,*/static/*
 max-complexity = 20
+docstring-convention=google
 
 [coverage:run]
 source = ./InvenTree