added readme

greenGridr/README.md

+# greenGridr
+
+Package of functions to process [NZ GreenGrid](https://www.otago.ac.nz/centre-sustainability/research/energy/otago050285.html) data.
+
+See package [DESCRIPTION](DESCRIPTION) file for (not a lot) more info.
+ 
+### Terms of code re-use
+
+Read the [License](LICENSE) file.
+
+[YMMV](http://en.wiktionary.org/wiki/YMMV)