Include image and link to exercise sheet

02_übung/README.md

-# Exercise Sheet 2
+<img src="ml.jpg" width=2000/><br>
+# Exercise Sheet 2 - Machine Learning
+Author: Samuel Innes <br>
+Email: dd257@stud.uni-heidelberg.de
+
+## <a href="_02_EXPML_ML_supervised.pdf">Link to Exercise sheet</a>
 
 ## :scroll: Step-by-Step Description
 1. <em>(Lines 9-22)</em>: Functions imported from [numpy](https://numpy.org/), [matplotlib](https://matplotlib.org/) and [scikit-learn](https://scikit-learn.org/stable/).