Raindrops is a real time stats package to show statistics for Rack HTTP
servers.  It is designed for preforking servers such as Rainbows! and
Unicorn, but should support any Rack HTTP server under Ruby and possibly
Rubinius (untested) on platforms supporting POSIX shared memory and
compiled with GCC (for atomic builtins).  Raindrops includes a
Struct-like Raindrops::Struct class that may be used standalone to
create atomic counters shared across any number of forked processes
under SMP.

1. build dependencies:
   1. libruby-devel
   2. ruby-tool-setup