Make db console work for all versions of ruby on Windows.

[#3999 state:committed]
Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

railties/lib/rails/commands/dbconsole.rb

 require 'erb'
 require 'yaml'
 require 'optparse'
+require 'rbconfig'
 
 module Rails
   class DBConsole
@@ -41,7 +42,7 @@ def start
 
       def find_cmd(*commands)
         dirs_on_path = ENV['PATH'].to_s.split(File::PATH_SEPARATOR)
-        commands += commands.map{|cmd| "#{cmd}.exe"} if RUBY_PLATFORM =~ /win32/
+        commands += commands.map{|cmd| "#{cmd}.exe"} if Config::CONFIG['host_os'] =~ /mswin|mingw/
 
         full_path_command = nil
         found = commands.detect do |cmd|