added key grouping for statistics Hash

Example:
store(“message”, {“count/private” => 1})
store(“message”, {“count/public” => 1})
fetch("message", 2.minutes.ago, Time.now)
  #=> { "count" => 2,
        "count/private" => 1,
        "count/public" => 1 }

lib/redistat.rb

@@ -36,6 +36,7 @@ module Redistat
   KEY_EVENT = ".event:"
   KEY_LEBELS = "Redistat.lables:"
   KEY_EVENT_IDS = ".event_ids"
+  GROUP_SEPARATOR = "/"
   
   class InvalidOptions < ArgumentError; end
   class RedisServerIsTooOld < Exception; end

lib/redistat/summary.rb

@@ -4,6 +4,7 @@ module Redistat
     
     def self.update_all(key, stats = {}, depth_limit = nil, connection_ref = nil)
       stats ||= {}
+      stats = inject_group_summaries(stats)
       depth_limit ||= key.depth
       return nil if stats.size == 0
       Date::DEPTHS.each do |depth|
@@ -20,5 +21,25 @@ module Redistat
       end
     end
     
+    def self.inject_group_summaries!(stats)
+      stats.each do |key, value|
+        parts = key.to_s.split(GROUP_SEPARATOR)
+        parts.pop
+        if parts.size > 0
+          sum_parts = []
+          parts.each do |part|
+            sum_parts << part
+            sum_key = sum_parts.join(GROUP_SEPARATOR)
+            (stats.has_key?(sum_key)) ? stats[sum_key] += value : stats[sum_key] = value
+          end
+        end
+      end
+      stats
+    end
+    
+    def self.inject_group_summaries(stats)
+      inject_group_summaries!(stats.clone)
+    end
+    
   end
 end

spec/summary_spec.rb

@@ -46,4 +46,25 @@ describe Redistat::Summary do
     end
   end
   
+  it "should inject stats key grouping summaries" do
+    hash = { "count/hello" => 3, "count/world"   => 7,
+             "death/bomb"  => 4, "death/unicorn" => 3,
+             :"od/sugar"   => 7, :"od/meth"      => 8 }
+    res = Redistat::Summary.send(:inject_group_summaries, hash)
+    res.should == { "count" => 10, "count/hello" => 3, "count/world"   => 7,
+                    "death" => 7, "death/bomb"   => 4, "death/unicorn" => 3,
+                    "od"    => 15, :"od/sugar"    => 7, :"od/meth"       => 8 }
+  end
+  
+  it "should properly store key group summaries" do
+    stats = {"views" => 3, "visitors/eu" => 2, "visitors/us" => 4}
+    Redistat::Summary.update_all(@key, stats, :hour)
+    summary = db.hgetall(@key.to_s(:hour))
+    summary.should have(4).items
+    summary["views"].should == "3"
+    summary["visitors"].should == "6"
+    summary["visitors/eu"].should == "2"
+    summary["visitors/us"].should == "4"
+  end
+  
 end