Update README.md

added missing hint for qpm as of #12

Author: Skycoder42

README.md

@@ -55,6 +55,7 @@ There are multiple ways to install the Qt module, sorted by preference:
 	8. Continue the setup and thats it! you can now use the module for all of your installed Kits for that Qt Version
 2. Download the compiled modules from the release page. **Note:** You will have to add the correct ones yourself and may need to adjust some paths to fit your installation!
 3. Build it yourself! **Note:** This requires perl to be installed. If you don't have/need cmake, you can ignore the related warnings. To automatically build and install to your Qt installation, run:
+    - `cd src/3rdparty && qpm install && cd ../..` (install qpm from here: https://github.com/Cutehacks/qpm)
 	- `qmake`
 	- `make qmake_all`
 	- `make`