1. Enter irc.freenode.org #redis and start talking with 'antirez' and/or 'pietern' to check if there is interest for such a feature and to understand the probability of it being merged. We'll try hard to keep Redis simple... so you'll likely encounter high resistance.
2. Drop a message to the Redis Google Group with a proposal of semantics/API.
3. If steps 1 and 2 are ok, use the following procedure to submit a patch:
a. Fork Redis on github ( http://help.github.com/fork-a-repo/ )
b. Create a topic branch (git checkout -b my_branch)
c. Push to your branch (git push origin my_branch)
d. Initiate a pull request on github ( http://help.github.com/send-pull-requests/ )