Docs - Explain fallback

Author: boukeversteegh

README.md

@@ -9,7 +9,8 @@ dockerized <command>
 
 ## Supported commands
 
-> If your favorite command is not included, it can be added very easily. See [Add a command](DEV.md).
+> If your favorite command is not included, it can be added very easily. See [Add a command](DEV.md).  
+> Dockerized will also fall back to over 150 commands defined in [jessfraz/dockerfiles](https://github.com/jessfraz/dockerfiles).
 
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