update readme

README.md

@@ -8,6 +8,7 @@ It is also helpful for local development to start multiple commands easily with
 
 - [robmuxinator](#robmuxinator)
   - [Installation](#installation)
+    - [Pip](#pip)
     - [Nix](#nix)
   - [Getting Started](#getting-started)
   - [Usage](#usage)
@@ -23,6 +24,8 @@ It is also helpful for local development to start multiple commands easily with
 
 ## Installation
 
+### Pip
+
 Install the robmuxinator with one simple command (execute in the `robmuxinator` package)
 ```
 sudo pip install .