Add links to exercises in readme

README.md

-# Øvingsrepo ITGK 2021
\ No newline at end of file
+# Øvingsrepo ITGK 2021
+
+- [Øving 1](./Ovinger/Oving1/_Oving1.ipynb)
+- [Øving 2](./Ovinger/Oving2/_Oving2.ipynb)
+- [Øving 3](./Ovinger/Oving3/_Oving3.ipynb)
+- [Øving 4](./Ovinger/Oving4/_Oving4.ipynb)
+- [Øving 5](./Ovinger/Oving5/_Oving5.ipynb)
+- [Øving 6](./Ovinger/Oving6/_Oving6.ipynb)
+- [Øving 7](./Ovinger/Oving7/_Oving7.ipynb)
+- [Øving 8](./Ovinger/Oving8/_Oving8.ipynb)