Update readme

Author: kylebarron

README.md

@@ -1,2 +1,7 @@
 # rstar
-Python bindings to the Rust rstar library for creating R* Trees
+
+Python bindings to the Rust [`rstar`](https://github.com/georust/rstar) library for creating R* Trees.
+
+At the moment, this is functional but very few Rust methods are wrapped. This is mainly used to test different methods for [spatially partitioning GeoParquet files](https://github.com/kylebarron/spatially-partitioned-geoparquet).
+
+Raise an issue to discuss exposing other methods.