Add maltzj/google-style-precommit-hook to the README

Fixes #226, #107

MOE_MIGRATED_REVID=197156700

Author: cushon

README.md

@@ -73,6 +73,9 @@ Implementation`.
 *   [Cosium/maven-git-code-format](https://github.com/Cosium/maven-git-code-format):
     A maven plugin that automatically deploys google-java-format as a pre-commit
     git hook.
+*   [maltzj/google-style-precommit-hook](https://github.com/maltzj/google-style-precommit-hook):
+    A pre-commit (pre-commit.com) hook that will automatically run GJF whenever
+    you commit code to your repository
 
 ### as a library