update readme

README.md

@@ -2,3 +2,20 @@ storyteller-web
 ===============
 This is our main user account monolith that we'll also bake other pieces into.
 
+Local development
+-----------------
+
+### Database migrations
+
+To reset the entire database (drop, migrate), run:
+
+```diesel database reset```
+
+To migrate at the current step and beyond: 
+
+```diesel migration run```
+
+To undo migrations at the current step: 
+
+```diesel migration redo```
+