add rails root to load path

in ruby 1.9, the load path doesn't include the current working directory

Change-Id: Ib61070da970af462dd58885477f97e83fe77b36f
Reviewed-on: https://gerrit.instructure.com/5841
Tested-by: Hudson <hudson@instructure.com>
Reviewed-by: Jon Jensen <jon@instructure.com>

config/boot.rb

@@ -2,6 +2,7 @@
 # Configure your app in config/environment.rb and config/environments/*.rb
 
 RAILS_ROOT = "#{File.dirname(__FILE__)}/.." unless defined?(RAILS_ROOT)
+$LOAD_PATH.unshift RAILS_ROOT
 
 module Rails
   class << self