clarified dependencies and usage

README.md

@@ -1,5 +1,8 @@
 # Debian Unattended
 Quality of Life scripts to automate the creation of an unattended version of any Debian ISO.
 
+## Requirements
+This repository requires `docker` installed. Check the [ansible](/ansible/ansible) repository if you don't have it.
+
 ## Usage
-Simply put an ISO file ending in `netinst.iso` and watch the magic happen by launching `./unattended.sh`
+Simply put a `preseed.cfg` and an ISO file ending in `netinst.iso` in the repo folder and watch the magic happen by launching `./unattended.sh`