Update README.md

README.md

+This Python script converts a TOUGH2 result file to VTK format for visualization with Paraview
+
+# Installing required Python packages
+```
+$ pip3 install pyyaml
+$ pip3 install pyevtk
+```
+
+# Config file
+The input file *config.yaml* contains some metadata of the results file.
+
+```
+filename_in: "/path/to/resultfile/openBC_prod_10yr.csv"
+filename_out: "/path/to/output/directory/no/extension/openBC_prod_10yr"
+
+# dimension
+npoint_d1: 80
+npoint_d2: 40
+npoint_d3: 15
+
+# layer thickness only in z direction
+layer_top: 5
+layer_middle: 5
+layer_bottom: 5
+```
+
+# Run the script
+```
+$ python3 results_to_vtk.py
+```
+The script will create a binary VTK file with the name: /path/to/output/directory/no/extension/openBC_prod_10yr.vts