update CONTRIBUTING - mostly to include 'add to CHANGELOG' but eneded up fleshing out additional sections.

Author: dlebauer

CHANGELOG.md

@@ -6,6 +6,20 @@ Once a new release is made this file will be updated to create a new `Unreleased
 
 For more information about this file see also [Keep a Changelog](http://keepachangelog.com/) .
 
+<!-- 
+sections to include in release notes:
+
+## [Unreleased]
+
+### Added
+
+### Fixed
+
+### Changed
+
+### Removed
+-->
+
 ## [Unreleased]
 
 ### Added

CONTRIBUTING.md

@@ -1,7 +1,45 @@
+# Contributing to SIPNET
 
+We welcome contributions to SIPNET. This document outlines the process for contributing to the SIPNET project.
+
+All contributors are expected to adhere to the PEcAn Project [Code of Conduct](https://github.com/PecanProject/pecan/blob/develop/CODE_OF_CONDUCT.md).
+
+## GitHub Workflow
+
+#### Branches
+
+The `master` branch is the default branch for SIPNET. Development should be done in feature branches. Feature branches should be named according to the following convention: `ISSUE#-feature-name`. For example, if you are working on issue #23, your branch should be named `23-event-handler`.
+
+#### Pull Requests
+
+Pull requests should be made from feature branches to the `master` branch. 
+
+Pull request descriptions should include a brief summary of the changes and a list of any issues that are resolved by the pull request. 
+
+Expectations for merging:
+- Pass all integration tests 
+- Approved by at least one other developer before being merged.
+- Include updates and additions to 
+  - Documentation
+  - Tests
+  - CHANGELOG.md 
+  
 ## Style Guide
 
-## Compiling
+#### Clang
+
+TBD #31
+
+#### Documentation
+
+What goes in **Doxygen**:
+- Documentation for functions, classes, and parameters.
+
+What goes in **docs/*md**:
+- User guides and tutorials.
+- Documentation of equations, theoretical basis, and parameters.
+
+## Compiling SIPNET binaries
 
 SIPNET uses `make` to build the model and documentation. There are also miscellaneous targets for running analysis workflows:
 
@@ -17,6 +55,8 @@ make help
 ```
 ## Testing
 
+Any new features (that are worth keeping!) should be covered by tests.
+
 SIPNET also uses `make` to build and run its unit tests. This can be done with the following commands:
 ```shell
 # Compile tests
@@ -32,3 +72,10 @@ If changes are made to the `modelStructure.h` file and unit tests are failing, t
 # Run this command from the root directory to update unit test versions of modelStructures.h
 tests/update_model_structures.sh
 ```
+
+## Releases
+
+- Use [Semantic Versioning v2](https://semver.org/) for SIPNET releases.
+- Tag releases with the version number `vX.Y.Z`.
+- Include content from `CHANGELOG.md` file.
+- Add compiled SIPNET binaries.