Move readme documentation on contributing out of the "product documen…

…tation" and back into the "repo readme"

README.md

@@ -18,3 +18,57 @@ Simplify building NodeJS applications on Google App Engine (GAE)
 - [gae-js-firebase-auth](https://mondo-mob.github.io/gae-js-docs/packages/gae-js-firebase-auth.html)
 - [gae-js-migrations](https://mondo-mob.github.io/gae-js-docs/packages/gae-js-migrations.html)
 - [gae-js-search](https://mondo-mob.github.io/gae-js-docs/packages/gae-js-gae-search.html)
+
+## Contributing
+
+This is a mono-repo using npm workspaces.
+Publishing is done using Atlassian Changesets (https://github.com/changesets/changesets).
+This helps be consistent with versioning and auto-generates changelogs.
+
+Here's the basic flow:
+
+1. Create one or more changesets
+
+- Once you've made your changes, create a changeset. You can create more than one changeset for a single version.
+
+```
+npx changeset
+```
+
+- From the cli tool, choose which packages to update and if major/minor/patch update
+- Enter summary for changes
+- Review and commit files
+
+2. Update package versions
+
+- Based on the changeset configuration - this will automatically version the packages.
+
+```
+npx changeset version
+```
+
+- Commit changes
+
+3. Build and publish
+
+Would be nice if this was done from CI but for now we do this locally.
+
+- Check you're running a suitable version of node/npm. If not switch and clear out old node_modules.
+- Build and publish
+
+```
+npm run publish-libs
+```
+
+### Adding new packages
+
+There's nothing automated to do this. Essentially you just need to add a new package to `/packages` folder but
+these steps should save some time:
+
+- Create new folder in `/packages`. e.g. `/packages/gae-js-new-thing`
+- Copy `package.json`, `tsconfig.json`, `tsconfig.prod.json`, `jest.config.json` from one of the existing packages
+- Update `package.json` to match desired name, version, dependencies, etc
+- Update `tsconfig.json` to match desired project references.
+- Create file src/index.ts and export some constant
+- Run `npm install` from root folder
+- Run `npm run build` from project folder