added readme to data folder

Author: cwittens

data/README.md

@@ -0,0 +1,25 @@
+# Dingemans.csv
+
+The data are taken from the experiments of Maarten Dingemans:
+
+```bibtex
+@techreport{dingemans1994comparison,
+  title={Comparison of computations with {B}oussinesq-like models and laboratory measurements},
+  author={Maarten W. Dingemans},
+  institution={Delft Hydraulics},
+  year={1994},
+  number={H1684.12},
+  url={http://resolver.tudelft.nl/uuid:c2091d53-f455-48af-a84b-ac86680455e9}
+}
+
+@book{dingemans1997water,
+  title={Water Wave Propagation Over Uneven Bottoms},
+  author={Maarten W. Dingemans},
+  year={1997},
+  volume={13},
+  doi={10.1142/1241},
+  publisher={World Scientific}
+}
+```
+
+The postions x1 to x6 are (3.04, 9.44, 20.04, 26.04, 30.44, 37.04) respectively.