How to update your local yum repo

There are a number of  great resources on how to set-up a local yum repo. This one from Digital Ocean is particularly good:
https://www.digitalocean.com/community/tutorials/how-to-set-up-and-use-yum-repositories-on-a-centos-6-vps

How though do you update the said yum repo? I needed to upgrade bash on some hosts to protect them against being ShellShock-ed. This required an upgrade to the local repo from which all these hosts retrieve their updates. Here’s what worked for me:

1. Download the rpm for the package you’d like to update in your repo
2. Place the rpm in your repo’s Packages folder
3. Then

   cd /the/repo/dir
   createrepo . #{Don't leave out the .}
   yum clean expire-cache
   yum list --showduplicates package 

4. The package you’ve added should appear under Available Packages. If it does, on the clients you can now run

   yum update package