update README

README.md

@@ -4,8 +4,22 @@
 pip install -r requirements.txt
 ```
 
-# Usage
+# Graph
 
 ```
 python graph.py Map.txt
 ```
+
+# Generation
+
+To generate a graph of N nodes run:
+
+```
+python generate.py N
+```
+
+By default this will give you a complete graph (every node connected to every other node) with 0 charging points. Specify the number of edges using `-e`.
+
+All options except for the names of the nodes are random.
+
+Run with `-h` to see other options.