adding back files to be reviewed

CONTRIBUTING.md

@@ -0,0 +1,46 @@
+# Contributing to OpenMC
+
+Welcome, and thank you for considering contributing to OpenMC! We look forward
+to welcoming new members to the community and will do our best to help you get
+up to speed.
+
+## Code of Conduct
+
+Participants in the OpenMC project are expected to follow and uphold the [Code
+of Conduct](CODE_OF_CONDUCT.md). Please report any unacceptable behavior to
+openmc@anl.gov.
+
+## Resources
+
+- [GitHub Repository](https://github.com/openmc-dev/openmc)
+- [Documentation](http://openmc.readthedocs.io/en/latest)
+- [User's Mailing List](openmc-users@googlegroups.com)
+- [Developer's Mailing List](openmc-dev@googlegroups.com)
+- [Slack Community](https://openmc.slack.com/signup) (If you don't see your
+  domain listed, contact openmc@anl.gov)
+
+## How to Report Bugs
+
+OpenMC is hosted on GitHub and all bugs are reported and tracked through the
+[Issues](https://github.com/openmc-dev/openmc/issues) listed on GitHub.
+
+## How to Suggest Enhancements
+
+We welcome suggestions for new features or enhancements to the code and
+encourage you to submit them as Issues on GitHub. However, it's important to
+recognize that our development team is relatively small and does not have
+unlimited time to devote to new feature suggestions. If you are interested in
+working on the feature you are requesting, indicate so in the issue and the
+development team will be happy to discuss it.
+
+## How to Submit Changes
+
+All changes to OpenMC happen through pull requests. For a full overview of the
+process, see the developer's guide section on [Contributing to
+OpenMC](http://openmc.readthedocs.io/en/latest/devguide/contributing.html).
+
+## Code Style
+
+Before you run off to make changes to the code, please have a look at our [style
+guide](http://openmc.readthedocs.io/en/latest/devguide/styleguide.html), which
+is used when reviewing new contributions.