Update requirements.txt

Author: jpadilla

{{ cookiecutter.repo_name }}/requirements.txt

@@ -1,6 +1,15 @@
+# Minimum Django and REST framework version
 Django>=1.6
 djangorestframework>=2.4.3
+
+# Test requirements
 pytest-django==2.6
 pytest==2.5.2
 pytest-cov==1.6
 flake8==2.2.2
+
+# wheel for PyPI installs
+wheel==0.24.0
+
+# MkDocs for documentation previews/deploys
+mkdocs==0.11.1