There are 3 reasons for doing this:
Neither of those versions is actively maintained.
Neither of those versions is actively used.
They cause us maintenance problems (like 1.8.6 not being able to install gems or 1.9.1 failing to compile (!)), and travis-ci.org is maintained by literally a handful of people in their spare time.
For example, we had to do the following:
- Figure out what is the most recent patch level of 1.9.1 that successfully builds with RVM. It turned out to be 1.9.1-p378.
- Figure out why 1.8.6 fails to install gems (https://gist.github.com/1223625)
In addition, compiling those two rubies takes time every time upgrade our VMs. It is simply not worth maintaining those two versions.
For 1.9.1 users, there is 1.9.3 and for those with 1.8.6... time to move beyond One True Ruby. Doing so will benefit the entire Ruby community.