update readme

Author: matthewstyler

README.md

@@ -73,7 +73,7 @@ See Command line Usage for full customization, below are some examples. Alter th
 Roads can be generated by providing a positive integer to the `roads=` argument. Roads are randomly seeded to begin
 and start at an axis (but not the same axis).
 
-A* pathfinding with a priority queue is used to generate the roads. The heuristic uses manhattan distance, and favours existing roads and similar elevations in adjacent tiles. 
+A* pathfinding with a priority queue, along with prim's algorithn and a minimum spanning tree is used to generate the roads. The heuristic uses manhattan distance, and favours existing roads and similar elevations in adjacent tiles. 
 
 Roads can be configured to include/exclude generating paths thorugh water, mountains and flora.