Run spellcheck to find common typos.

.travis.yml

@@ -4,6 +4,7 @@ python:
   - "3.6"
 install:
   - pip install coveralls
+  - pip install -r requirements.txt
 script:
   coverage run --source=bitstruct setup.py test
 after_success:

Makefile

@@ -1,6 +1,7 @@
 test:
 	python2 setup.py test
 	python3 setup.py test
+	codespell -d $$(git ls-files)
 
 release-to-pypi:
 	python setup.py sdist

README.rst

@@ -115,6 +115,30 @@ values:
     >>> unpack('u1u3u4s16', byteswap('12', packed))
     (1, 2, 3, 256)
 
+Contributing
+============
+
+#. Install prerequisites.
+
+   .. code-block:: text
+
+      pip install -r requirements.txt
+
+#. Fork the repository.
+
+#. Implement the new feature or bug fix.
+
+#. Implement test case(s) to ensure that future changes do not break
+   legacy.
+
+#. Run the tests.
+
+   .. code-block:: text
+
+      make test
+
+#. Create a pull request.
+
 .. |buildstatus| image:: https://travis-ci.org/eerimoq/bitstruct.svg
 .. _buildstatus: https://travis-ci.org/eerimoq/bitstruct
 

requirements.txt

@@ -0,0 +1 @@
+codespell