update readme

readme.md

@@ -60,10 +60,21 @@ It should download the software package and extract it and install it into you `
 
 If needed you can create hook scripts. The working directory is `${installdir}` that you can use relative pathes to point to your files in the the extracted sources.
 
+To access other ressources you can user these variables:
+
+```txt
+${selfdir}     application root of deployment scripts
+${projectdir}  project config dir i.e. [path]/profiles/myapp
+```
+
+For hooks you can create files with pre defined names. A hook script must have executable rights. You get a hint message if it does not exist or has no x permission. A missing hook script does not result in an error.
+
 * profiles/myapp/tasks_preinstall.sh - do something before extracting the archive.
 * profiles/myapp/tasks_config.sh - replace config files (see below)
 * profiles/myapp/tasks_postinstall.sh - do postinstall actions before finishing
 
+Example:
+
 ```txt
 # ----------------------------------------------------------------------
 # TASKS :: POST INSTALL ACTIONS