add a few things to cargo.toml

Author: nikomatsakis

Cargo.toml

@@ -6,6 +6,8 @@ homepage = "https://github.com/nikomatsakis/ena"
 repository = "https://github.com/nikomatsakis/ena"
 version = "0.8.0"
 authors = ["Niko Matsakis <niko@alum.mit.edu>"]
+readme = "README.md"
+keywords = ["unification", "union-find"]
 
 [features]
 congruence-closure = [ "petgraph" ]