updated readme

README.md

@@ -71,6 +71,13 @@ Make sure that with every change/recompilation you make in `binary_c`, you also
 ## Documentation
 Look in the docs/ directory. Within the build/html/ there is the html version of the documentation. The 
 
+## Development:
+If you want to contribute to the code, then it is recommended that you install the packages in `development_requirements.txt`:
+
+```
+pip install -r development_requirements.txt
+```
+
 ## FAQ/Issues:
 Building issues with binary_c itself: 
 - see the documentation of binary_c (in doc/).