Fix typo

README.md

 
 *overduer* is heavily inspired by Git's interactive rebase: it uses
 *vipe* utility to open simple line-based list that you can edit and save,
-while lines that you did not edit or lines that you deleted are ignorred.
+while lines that you did not edit or lines that you deleted are ignored.
 
 This gives perfect balance between speed and safety: First, it only
 takes few seconds to deal with tasks you are immediately sure about and