Add a CONTRIBUTING.md page (#123)

* Add a CONTRIBUTING.md page

docs/CONTRIBUTING.md

@@ -0,0 +1,102 @@
+# Testing
+
+## Make a RC Release including a wp_launch_check.phar
+Make your changes to the `wp_launch_check` source code.
+
+Temporarily update the logic so the `wp_launch_check.phar` is created on all branches. In `.github/workflows/validate.yml`, replace the two branch names with one line:
+```
+- '**'
+```
+
+Create a Release Candidate tag based on your source branch.  The RC number should be one more, incremented on the patch version, than the most recent non-RC tag.
+
+```
+cd wp_launch_check
+git fetch origin
+git tag
+git checkout <source-branch>
+git pull
+git tag -a "v1.2.3-RC1" -m "Version 1.2.3-RC1"
+git push origin v1.2.3-RC1
+```
+When the tag is pushed, GitHub Actions will automatically create a Release including a `wp_launch_check.phar` file.
+
+Monitor https://github.com/pantheon-systems/wp_launch_check/actions.  Watch for your tag’s workflow to complete.  If there are any failing tests, satisfy the failing test or rerun the job.
+
+Review https://github.com/pantheon-systems/wp_launch_check/releases and ensure a `wp_launch_check.phar` file was created.
+
+## Generate a Quay tag for cos-wpcli based on the RC above
+
+If necessary, clone https://github.com/pantheon-systems/cos-framework-clis locally.
+
+Checkout a new branch called `wplc-1.2.3-RC1`
+
+In `wpcli/Dockerfile`, bump the version of WP-CLI.
+
+In `.circleci/config.yml`, do the following so the non-default branch will push a tag to Quay.
+1. Remove the if/fi lines around  `make push-wpcli-tags`
+2. Remove two spaces of indentation prior to `make push-wpcli-tags`
+
+Push the branch to GitHub.  Do not make a PR.
+
+Browse to the [branches page in GitHub](https://github.com/pantheon-systems/cos-framework-clis/branches) and click into your branch.
+
+Above the listing of files in the branch, look next to the commit hash for an orange circle, green checkmark, or a red x.  Click the colored icon to see the jobs running for this branch
+
+Click Details next to the `ci/circleci: build-wpcli` job.
+
+In the `push image to quay.io` step, look for the line that begins with `docker push` and note the tag number after `cos-wpcli:`
+
+You can confirm this tag in Quay by browsing to https://quay.io/getpantheon/cos-wpcli
+
+## Test your code
+
+Use [tagged deploys](https://github.com/pantheon-systems/infrastructure/blob/master/docs/tagged-deploys.md) for the `wpcli` container on an `appserver` associated with a test site in production or on your sandbox.
+
+Test that your code wp_launch_check code is working as expected.
+
+Take screenshots to be used in the PRs during the Deploying steps below.
+
+## Cleanup
+
+Delete the RC tag in wp_launch_check on your local and in GitHub:
+```
+git tag -d v1.2.3-RC1
+git push origin :refs/tags/v1.2.3-RC1
+```
+
+Delete the RC release on the wp_launch_check Releases page in GitHub.
+
+Delete the RC branch on the cos-framework-clis Branches page in GitHub.
+
+# Deploying
+
+## Make a Release including a wp_launch_check.phar
+
+Undo any changes you temporarily made above to `.github/workflows/validate.yml`.
+
+Open a PR, get approval, and merge your source branch into the main branch.
+
+Create a Release tag based on the main branch.  Use the same tag number used during testing, but omit the -RC# part.
+```
+cd wp_launch_check
+git fetch origin
+git tag
+git checkout main
+git pull
+git tag -a "v1.2.3" -m "Version 1.2.3"
+git push origin v1.2.3
+```
+Monitor https://github.com/pantheon-systems/wp_launch_check/actions.  Watch for your tag’s workflow to complete.  If there are any failing tests, satisfy the failing test or rerun the job.
+
+Review https://github.com/pantheon-systems/wp_launch_check/releases and ensure a `wp_launch_check.phar` file was created.
+
+## Bump the version of Launch Check
+
+In your clone of https://github.com/pantheon-systems/cos-framework-clis, checkout a new branch based off master called `wplc-1.2.3`.
+
+In `wpcli/Dockerfile`, bump the version of wp_launch_check
+
+Push the branch to GitHub.
+
+Open a PR referencing the above PR, get approval, and merge your source branch into the master branch.