Capistrano: Host key verification failed

If you ever encounter the error message below when deploying using Capistrano, here's a solution for you.

 ** [12.12.12.12 :: err] Host key verification failed.
 ** [12.12.12.12 :: err] fatal: The remote end hung up unexpectedly
 ** [12.12.12.12 :: err] fetch-pack from 'git@github.com:abc/xyz.git' failed.

This seems to mean that the RSA key fingerprint needs to be verified (I'm not 100% sure on this). My solution is to do git clone on the server and confirm the fingerprint prompt, but there is a better approach. You can also do ssh git@github.com and confirm the prompt.