Sourcegraph is code search and intelligence across all your code, integrated with your code host (even giving you IDE-like hovers, definitions, references, etc., when viewing code files and diffs on GitHub/etc.).
In addition to the things mentioned in the announcement, we've been making steady improvements to code intelligence. Check out https://about.sourcegraph.com/docs/code-intelligence.
One of the things we see is that basically 100% of devs at Google and Facebook use those companies' internal Sourcegraph-like tools for code search/intelligence, and it makes them a lot happier and more productive as devs. We think 100% of devs at every company should have amazing code search and intelligence.
For Ruby, we haven't investigated the situation in a few months. Last time, we checked out https://github.com/mtsmfm/language_server-ruby but it was not far enough along. We maintain a table of language servers at http://langserver.org/, and once they have support for hovers, definitions, and references, we begin to plan to integrate them. We'll be releasing a roadmap for Sourcegraph language support soon with a lot more docs for how to integrate existing language servers, too.
-- Linda, PM @ Sourcegraph