create template for exercises

src/1_einstein_model.md

@@ -117,3 +117,11 @@ ax.set_xlabel('$T[K]$')
 ax.set_ylabel('$C/k_B$')
 ax.set_ylim((0, 3));
 ```
+
+## Exercises
+
+### Exercise title
+
+### Exercise title
+
+### Exercise title

src/2_debye_model.md

@@ -128,3 +128,11 @@ ax.legend(loc='lower right')
 pyplot.hlines([3], 0, 1.5, linestyles='dashed')
 draw_classic_axes(ax, xlabeloffset=0.3)
 ```
+
+## Exercises
+
+### Exercise title
+
+### Exercise title
+
+### Exercise title