docs: readme

Author: AriPerkkio

README.md

@@ -1,2 +1,40 @@
 # webcontainer-ecosystem-ci
-WebContainer Ecosystem CI
+
+This repository is used to run tests for WebContainer ecosystem projects
+
+## Github workflow
+
+### Scheduled
+
+Workflows are sheduled to run automatically every Monday, Wednesday and Friday.
+
+### Manually
+
+- open [workflow](../../actions/workflows/ecosystem-ci.yml)
+- click 'Run workflow' button on top right of the list
+- select suite to run in dropdown
+- start workflow
+
+### Shell script
+
+- clone this repo
+- run `pnpm i`
+- run `pnpm test` to run all suites
+- or `pnpm test <suitename>` to select a suite
+- or `tsx ecosystem-ci.ts`
+
+You can pass `--release <version>` to select a specific `@webcontainer/api` version to use.
+
+The repositories are checked out into `workspace` subdirectory as shallow clones
+
+## How to add a new integration test
+
+- check out the existing [tests](./tests) and add one yourself. Thanks to some utilities it is really easy
+- once you are confidente the suite works, add it to the lists of suites in the [workflows](../../actions/)
+
+## Credits
+
+This project is inspired and based on:
+
+- https://github.com/vitest-dev/vitest-ecosystem-ci
+- https://github.com/vitejs/vite-ecosystem-ci