Add Dockerized OpenTofu runner

README.md

@@ -89,6 +89,48 @@ Destroy:
 tofu destroy
 ```
 
+## Docker Usage
+
+You can run OpenTofu from a Docker container instead of installing it on the host.
+
+Build the runner image:
+
+```bash
+docker compose build tofu
+```
+
+Run `init` for the default `dev` environment:
+
+```bash
+docker compose run --rm tofu init
+```
+
+Run `plan`:
+
+```bash
+docker compose run --rm tofu plan
+```
+
+Run `apply`:
+
+```bash
+docker compose run --rm tofu apply
+```
+
+Select another environment with `QUANTUM_ENV`:
+
+```bash
+QUANTUM_ENV=stg docker compose run --rm tofu plan
+QUANTUM_ENV=prd docker compose run --rm tofu plan
+```
+
+On PowerShell:
+
+```powershell
+$env:QUANTUM_ENV="stg"
+docker compose run --rm tofu plan
+```
+
 ## Quick Tests
 
 List buckets: