Add development section

Author: abetlen

docs/index.md

@@ -49,6 +49,14 @@ pip install llama-cpp-python
 }
 ```
 
+## Development
+
+```bash
+git clone git@github.com:abetlen/llama-cpp-python.git
+git submodule update --init --recursive
+# Will need to be re-run any time vendor/llama.cpp is updated
+python3 setup.py develop
+```
 
 ## API Reference