Ask people to add an entry to the change log

CONTRIBUTING.md

@@ -1,15 +1,15 @@
 We welcome your contributions to help improve Publify.
 
-
 ## Pull Requests
 
 If you would like to send a pull request, please do, and follow these steps:
 
 1. Fork the repo
-2. Open an issue or pick up one from [the open issues list](https://github.com/publify/publify/issues)
-3. Mention your issue in the PR
+2. Open an issue or pick one up from [the open issues list][issues]
+3. Mention your issue in the pull request
 4. Add tests where applicable
-5. Ensure the build passes before sending your PR
+5. Add or update an entry for your change in CHANGELOG.md
+6. Ensure the build passes before sending your pull request
 
 ## Bug reports
 
@@ -19,4 +19,6 @@ When reporting a bug, please include as much of the following as you can:
 * Page(s) the bug occurs
 * Steps taken to reproduce the error or bug
 * Environment settings and versions you are using
-* Any relevant error logs or screenshots
+* Any relevant error logs or screenshots
+
+[issues]: https://github.com/publify/publify/issues