Updated installation in README.md

README.md

@@ -13,6 +13,11 @@ python3 setup.py install
 ```
 This will copy the required package files to your python installation point (or, in case of a virtual environment, to the _lib_ directory of the env folder) and install all requirements.
 
+When you want to use devices which communicate over I²C, you probably first have to enable with `raspi-config`:
+- _Interface Options_
+- _I2C_
+- **Yes** and **OK**
+
 That's it! Now you can use the library in Python by importing it:
 ```python3
 import RPiGPIOmakertools