README: explicitely mention the templates option as well

Otherwise the templates from /usr/share/grml-live/templates
are used (and might not be present).

README.md

@@ -15,11 +15,12 @@ additional software and your very own configuration files.
 
 Further information is available from http://grml.org/grml-live/
 
-In case you want to run grml-live directly from the checkout (after
-making sure all dependencies are installed), you should set
-`GRML_FAI_CONFIG` so that it does not use the config files of an
-installed `grml-live` package:
+In case you want to run grml-live directly from the checkout
+(after making sure all dependencies are installed), you should
+set `GRML_FAI_CONFIG`, the `SCRIPTS_DIRECTORY` and the templates
+option so that it does not use the config files of an installed
+`grml-live` package:
 
     # export GRML_FAI_CONFIG=$(pwd)/etc/grml/fai
     # export SCRIPTS_DIRECTORY=$(pwd)/scripts
-    # ./grml-live -s sid -a amd64 -c GRMLBASE,GRML_FULL,AMD64
+    # ./grml-live -s sid -a amd64 -c GRMLBASE,GRML_FULL,AMD64 -t $(pwd)/templates/