docs: Add status-badge and run instructions (#42)

Author: limakzi

README.md

@@ -1 +1,13 @@
 ## gap-docker
+
+[![docker-build](https://github.com/limakzi/gap-docker/actions/workflows/main.yaml/badge.svg)](https://github.com/limakzi/gap-docker/actions/workflows/main.yaml)
+
+* Run a container:
+
+```
+docker run -it ghcr.io/limakzi/gap-docker:4.13.1
+```
+
+```
+docker run -it ghcr.io/limakzi/gap-docker:4.14.0
+```