Missing contributor guidelines

[paretech]

To help our project contributors do good work, I propose adding a CONTRIBUTING.md document that specifies general contribution expectations and workflow. The initial draft of CONTRIBUTING.md would not be comprehensive but instead provide an initial place that future revisions can be made.

CONTRIBUTING.md would be inspired from a number of resources and projects that also have such a document. For example, see the list of resources at the bottom of the issue body.

The CONTRIBUTING.md file would be placed at the root of the repo and will therefor automatically generate a link to the file when someone opens a pull request or creates an issue.

Additional changes to the project may be required to bring it into alignment with the contributing guidelines, these changes will be handled as subsequent issues and not part of this issue.

• https://help.github.com/articles/setting-guidelines-for-repository-contributors/
• https://mozillascience.github.io/working-open-workshop/contributing/
• https://devguide.python.org/documenting/
• https://docs.djangoproject.com/en/dev/internals/contributing/
• https://docs.djangoproject.com/en/dev/internals/contributing/committing-code/
• https://github.com/activeadmin/activeadmin/blob/master/CONTRIBUTING.md
• https://gist.github.com/PurpleBooth/b24679402957c63ec426
• https://github.com/opengovernment/opengovernment/blob/master/CONTRIBUTING.md
• https://github.com/rails/rails/blob/master/CONTRIBUTING.md
• https://github.com/atom/atom/blob/master/CONTRIBUTING.md
• https://help.github.com/articles/setting-guidelines-for-repository-contributors/
• https://github.com/agis/git-style-guide

[paretech]

Issue resolved by pull request #22.