Add mypy to the local dependencies

{{cookiecutter.project_slug}}/README.rst

@@ -32,6 +32,15 @@ Setting Up Your Users
 
 For convenience, you can keep your normal user logged in on Chrome and your superuser logged in on Firefox (or similar), so that you can see how the site behaves for both kinds of users.
 
+Type checks
+^^^^^^^^^^^
+
+Running type checks with mypy:
+
+::
+
+  $ mypy {{cookiecutter.project_slug}}
+
 Test coverage
 ^^^^^^^^^^^^^
 

{{cookiecutter.project_slug}}/requirements/local.txt

@@ -11,6 +11,7 @@ psycopg2-binary==2.7.5  # https://github.com/psycopg/psycopg2
 
 # Testing
 # ------------------------------------------------------------------------------
+mypy==0.610  # https://github.com/python/mypy
 pytest==3.6.2  # https://github.com/pytest-dev/pytest
 pytest-sugar==0.9.1  # https://github.com/Frozenball/pytest-sugar
 

{{cookiecutter.project_slug}}/setup.cfg

@@ -5,3 +5,17 @@ exclude = .tox,.git,*/migrations/*,*/static/CACHE/*,docs,node_modules
 [pycodestyle]
 max-line-length = 120
 exclude = .tox,.git,*/migrations/*,*/static/CACHE/*,docs,node_modules
+
+[mypy]
+python_version = 3.6
+check_untyped_defs = True
+ignore_errors = False
+ignore_missing_imports = True
+strict_optional = True
+warn_unused_ignores = True
+warn_redundant_casts = True
+warn_unused_configs = True
+
+[mypy-*.migrations.*]
+# Django migrations should not produce any errors:
+ignore_errors = True