Update README.md

README.md

@@ -10,6 +10,7 @@ usually marked with `???`.
 | lecture                         | package                                                           |
 |---------------------------------|-------------------------------------------------------------------|
 | 2: Functional Data Structures   | [`datastructures`](src/main/scala/datastructures)                 |
+| 3: Error Handling               | [`errors`](src/main/scala/errors)                                 |
 
 ## Usage tips:
 To keep your local solutions to the exercises when pulling from the repository,