Fix installation instructions

Author: werrolf

README.md

@@ -3,14 +3,9 @@
 Handle, edit and run own SQL's within of mapbender3.
 
 
-## Installation 
-* First you need installed mapbender3-starter https://github.com/mapbender/mapbender-starter#installation project
-* Add required module to mapbender
+## Installation
+Use `composer require mapbender/query-builder` and register MapbenderQueryBuilderBundle with the Symfony application kernel.
 
-```sh
-$ cd application/
-$ ../composer.phar require "mapbender/query-builder"
-```
 
 ## Contributing