Document new release workflow

Author: egiurleo

README.md

@@ -377,6 +377,21 @@ After checking out the repo, run `bin/setup` to install dependencies. Then, run
 
 To install this gem onto your local machine, run `bundle exec rake install`.
 
+## Releasing
+
+### Bump the gem version
+- [ ] Locally, update the version number in [`version.rb`](https://github.com/Shopify/spoom/blob/main/lib/spoom/version.rb)
+- [ ] Run `bundle install` to update the version number in `Gemfile.lock`
+- [ ] Commit this change with the message `Bump version to vx.y.z`
+- [ ] Push this change directly to main or open a PR
+
+### Create a new tag
+- [ ] Locally, create a new tag with the new version number: `git tag vx.y.z`
+- [ ] Push this tag up to the remote `git push origin vx.y.z`
+
+### Release workflow will run automatically
+We have a [release workflow](https://github.com/Shopify/spoom/actions/workflows/release.yml) that will publish your new gem version to rubygems.org via [Trusted Publishing](https://guides.rubygems.org/trusted-publishing/). This workflow must be approved by a member of the Ruby and Rails Infrastructure team at Shopify before it will run. Once it is approved, it will automatically publish a new gem version to rubygems.org and create a new GitHub release.
+
 ## Contributing
 
 Bug reports and pull requests are welcome on GitHub at https://github.com/Shopify/spoom. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](http://contributor-covenant.org) code of conduct.