introduce rack:cache as a default, so users don't need to configure apache or nginx

under rack cache we are able to serve 620reqs a second per thin (on my machine) before it 12 (on my machine)

reorganised so mini profilers can be cleanly disabled from config file

added caching for categories index

move production.rb to production.sample.rb

lib/discourse_redis.rb

@@ -11,7 +11,12 @@ class DiscourseRedis
   end
 
   def self.config
-    YAML.load(ERB.new(File.new("#{Rails.root}/config/redis.yml").read).result)[Rails.env]
+    @config ||= YAML.load(ERB.new(File.new("#{Rails.root}/config/redis.yml").read).result)[Rails.env]
+  end
+
+  def self.url(config=nil)
+    config ||= self.config
+    "redis://#{(':' + config['password'] + '@') if config['password']}#{config['host']}:#{config['port']}/#{config['db']}"
   end
 
   def initialize
@@ -19,6 +24,10 @@ class DiscourseRedis
     @redis = DiscourseRedis.raw_connection(@config)
   end
 
+  def url
+    self.class.url(@config)
+  end
+
   # prefix the key with the namespace
   def method_missing(meth, *args, &block)
     if @redis.respond_to?(meth)
@@ -52,8 +61,5 @@ class DiscourseRedis
     redis_store
   end
 
-  def url
-    "redis://#{(':' + @config['password'] + '@') if @config['password']}#{@config['host']}:#{@config['port']}/#{@config['db']}"
-  end
 
 end