Add notes on mandatory packages to readme

Author: VicDeo

README.md

@@ -12,6 +12,10 @@ An ownCloud app to work with office documents alone and/or collaboratively.
 **Solution**: Try to disable gzip for Documents app by adding the following line to your .htaccess:  
 `SetEnvIf Request_URI .*/apps/documents/ajax/.* no-gzip dont-vary`
 
+**Problem**: Doc(x) support doesn't work__
+**Solution**: Install at least  `libreoffice-common` and  `libreoffice-writer` packages for your distro.__
+If you don't want to mess around with dependencies, you need simply install `unoconv` package. It will do the trick for you.
+
 ### How to add more fonts ###
 + Upload font files to **documents/css/fonts** directory
 + Edit **documents/css/fonts.css** adding `@font-face` rule for each uploaded file