URL shortener for an internal company tool

Design a small URL shortener for an internal company tool that handles about 1,000 new links per day and a few thousand redirects per day. A user pastes a long URL and gets back a short code; visiting the short code redirects to the original. The system is read-heavy (far more redirects than creates) and links never expire. Walk through the components, the data model, and how you generate short codes.