forum_ruby_version defaults to 1.9.3, out of support since Feb 2015

[fghaas]

The default for forum_ruby_version in the forum role is 1.9.3-p551. Support for Ruby 1.9.3 ended in February 2015, and running anything on this Ruby version must be considered a security risk.

[tobz]

We're in the process of moving back to 2.x. The long story short is that there was some weirdness going on with memory usage when we switched to 2.3 before.