update rails 4

ensure you clear the tmp/cache folder on each bench (so results are correct, there is an incompat upgrade)
add facter gem which will be used to collect hardware data from the bencher

script/bench.rb

@@ -2,12 +2,21 @@ require "socket"
 require "csv"
 require "yaml"
 
-@timings = {}
-
 def run(command)
   system(command, out: $stdout, err: :out)
 end
 
+begin
+  require 'facter'
+rescue LoadError
+  run "gem install facter"
+  puts "just installed the facter gem, please re-run script"
+  exit
+end
+
+@timings = {}
+
+
 def measure(name)
   start = Time.now
   yield
@@ -98,6 +107,8 @@ def bench(path)
 end
 
 begin
+  # critical cause cache may be incompatible or something
+  `rm -fr tmp/cache`
   pid = spawn("bundle exec thin start -p #{@port}")
 
   while port_available? @port
@@ -119,6 +130,8 @@ begin
     "rails4?" => ENV["RAILS4"] == "1"
   }.to_yaml)
 
+  # TODO include Facter.to_hash ... for all facts
+
 ensure
   Process.kill "KILL", pid
 end