Update README with Gem badge

README.md

@@ -1,5 +1,7 @@
 # Tdigest
 
+[![Gem Version](https://badge.fury.io/rb/tdigest.svg)](https://badge.fury.io/rb/tdigest)
+
 Ruby implementation of Ted Dunning's [t-digest](https://github.com/tdunning/t-digest) data structure.
 
 Inspired by the [Javascript implementation](https://github.com/welch/tdigest) by [Will Welch](https://github.com/welch)
@@ -39,7 +41,7 @@ To install this gem onto your local machine, run `bundle exec rake install`. To
 
 ## Contributing
 
-Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/tdigest. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the [Contributor Covenant](contributor-covenant.org) code of conduct.
+Bug reports and pull requests are welcome on GitHub at https://github.com/castle/tdigest.
 
 
 ## License