fix readme

README.md

@@ -13,7 +13,7 @@ Afterwards, source the ```install``` directory.
 ## Preparation
 Please note that you first have to install the proper Firmware onto the Arbotix-M Robotcontroller Board.
 
-To do that please follow the instructions on the (PhantomX Reactor Arm Repository)[https://github.com/RobotnikAutomation/phantomx_reactor_arm].
+To do that please follow the instructions on the [PhantomX Reactor Arm Repository](https://github.com/RobotnikAutomation/phantomx_reactor_arm).
 
 ## Usage
 1. Start the Webcam Tracker