Add a makefile target for testing the readme

Makefile

@@ -11,6 +11,9 @@ test:
 	# the -k flag, like "py.test -k test_path_is_not_double_encoded"
 	pipenv run py.test tests
 
+test-readme:
+	pipenv run python setup.py check -r -s
+
 coverage:
 	pipenv run py.test --cov-config .coveragerc --verbose --cov-report term --cov-report xml --cov=requests tests
 

Pipfile

@@ -11,3 +11,4 @@ pytest-mock = "*"
 pytest-cov = "*"
 pysocks = "*"
 alabaster = "*"
+readme_renderer = "*"