Move changelog and diagram information to contributing.md

documentation/contributing.md

@@ -22,4 +22,29 @@ conform to the
 1. Core migrations should be committed in their `goose fix`ed form. To do this, run `make version_migrations` which
 converts timestamped migrations to migrations versioned by an incremented integer.
 
+## Diagrams
+- Diagrams were created with [draw.io](draw.io).
+- To update a diagram:
+  1. Go to [draw.io](draw.io).
+  1. Click on *File > Open from* and choose the location of the diagram you want to update.
+  1. Once open in draw.io, you may update it.
+  1. Export the diagram to this repository's directory and add commit it.
+
+
+## Generating the Changelog
+We use [github-changelog-generator](https://github.com/github-changelog-generator/github-changelog-generator) to generate release Changelogs. To be consistent with previous Changelogs, the following flags should be passed to the command:
+
+```
+--user vulcanize
+--project vulcanizedb
+--token {YOUR_GITHUB_TOKEN}
+--no-issues
+--usernames-as-github-logins
+--since-tag {PREVIOUS_RELEASE_TAG}
+```
+
+For more information on why your github token is needed, and how to generate it see [https://github
+.com/github-changelog-generator/github-changelog-generator#github-token](https://github.com/github-changelog-generator/github-changelog-generator#github-token).
+
+## Code of Conduct
 VulcanizeDB follows the [Contributor Covenant Code of Conduct](https://www.contributor-covenant.org/version/1/4/code-of-conduct).