Add installation instructions

Fixes #11

README.md

@@ -2,6 +2,20 @@
 
 A set of [pre-commit](http://pre-commit.com) hooks for Docker services
 
+# Installation
+
+Add the following to your `.pre-commit-config.yaml` file
+
+```yaml
+  - repo: https://github.com/iamthefij/docker-pre-commit
+    rev: master
+    hooks:
+      - id: docker-compose-check
+```
+
+and then run `pre-commit autoupdate`.
+
+
 ## Hooks
 
 ### docker-compose-check