fix installation instruction in readme

README.md

@@ -61,12 +61,19 @@ Detailed installation instructions, including how to install Python from scratch
 are described in the [detailed installation manual](docs/install-manual-detailed.md).
 
 
-If you know what you are doing, you can install as follows:
+If you know what you are doing, you can install as a package as follows:
 
 ```
-python setup.py
+python setup.py install
 ```
 
+Or in development mode, install from your working directory
+
+```
+pip install -e ./
+```
+
+
 Or create a binary wheel distribution package with:
 
 ```