Add contribution guidelines (CONTRIBUTING.md).

CHANGELOG.md

@@ -30,6 +30,8 @@ Fixed a bug that kept the `-f` (stop after first failure) flag from
 stopping the test runner immediately when a failure occured just
 before running a new suite.
 
+A file with contribution guidelines (`CONTRIBUTING.md`) was added.
+
 
 ## v1.1.1 - 2016-02-14
 

CONTRIBUTING.md

@@ -0,0 +1,75 @@
+# Contributing to greatest
+
+Thanks for taking time to contribute to greatest!
+
+Please send patches or pull requests against the `develop` branch. This
+makes it easier to avoid interface changes until they can be reflected
+in version number updates.
+
+Sending changes via patch or pull request acknowledges that you are
+willing and able to contribute it under this project's license. (Please
+don't contribute code you aren't legally able to share.)
+
+
+## Bug Reports
+
+Please report bugs at [the Issues page][issues].
+
+[issues]: https://github.com/silentbicycle/greatest/issues).
+
+If you are reporting a bug, please include:
+
++ Your operating system name and version.
+
++ Your compiler version and target platform.
+
++ Any details about your local setup that might be helpful in
+  troubleshooting.
+
++ Detailed steps to reproduce the bug.
+
+
+## Documentation
+
+Improvements to the documentation are welcome. So are requests for
+clarification -- if the docs are unclear or misleading, that's a
+potential source of bugs.
+
+
+## Portability
+
+greatest tries to assume little about its environment. It targets ANSI C
+(C89) as a baseline, and features that are specific to C99 or later need
+to be wrapped in a version check.
+
+It doesn't require a particular OS, or that there is an OS at all. (It
+may be running tests on an embedded system without an RTOS.) It uses
+`fprintf(3)` for reporting, that's about it.
+
+Improvements that don't fit the portability requirements can go in
+`contrib/`, just not the main `greatest.h` header.
+
+
+## contrib/: Extensions and Other Tools
+
+There is a `contrib/` directory for extensions. This could include
+scripts that generate test templates, add formatting to the reports, or
+better integrate greatest into build / continuous integration systems.
+Extension libraries that depend on dynamic allocation or
+platform-specific features can also go here.
+
+Please include a license in any standalone scripts or extensions.
+
+
+## Versioning & Compatibility
+
+The versioning format is MAJOR.MINOR.PATCH.
+
+Improvements or minor bug fixes that do not break compatibility with
+past releases lead to patch version increases. API changes that do not
+break compatibility lead to minor version increases and reset the patch
+version, and changes that do break compatibility lead to a major version
+increase.
+
+The version will be increased during the merge to master, as part of
+the release process.