Add usage info to readme

README.md

@@ -10,3 +10,14 @@ usually marked with `???`.
 | lecture                         | package                                                           |
 |---------------------------------|-------------------------------------------------------------------|
 | 2: Functional Data Structures   | [`datastructures`](src/main/scala/datastructures)                 |
+
+## Usage tips:
+To keep your local solutions to the exercises when pulling from the repository,
+use
+```shell
+git pull --rebase --autostash
+```
+This will keep both commited and uncommited changes.
+
+If you are using Intellij IDEA, "rebase" is available as option in the update
+dialog and stashing is default.