drop Ruby 1.9.3 support, require 2.0+ for now

Ruby 1.9.3 was released nearly a decade ago, so there's probably
few (if any) legacy users left, and they can continue using old
versions of unicorn.  We'll be able to take advantage of some
Ruby 2.0+-only features down the road (and hopefully 2.3+).

Also, I no longer have a installation of Ruby 1.8 and getting it
working probably isn't worth the effort, so 4.x support is gone.

1 files changed, 1 insertions, 1 deletions

diff --git a/HACKING b/HACKING
index 976bf92..7c41eba 100644
--- a/HACKING
+++ b/HACKING
@@ -63,7 +63,7 @@ becomes unavailable.
 
 === Ruby/C Compatibility
 
-We target mainline Ruby 1.9.3 and later.  We need the Ruby
+We target C Ruby 2.0 and later.  We need the Ruby
 implementation to support fork, exec, pipe, UNIX signals, access to
 integer file descriptors and ability to use unlinked files.