Update redis_store.rb to reuse single connection

Each time the redis method got hit, it would spawn a new redis connection. This simple fix reuses a single connection per process. Should stop connection leaks and redundant connections to the redis provider. 

Ruby/lib/mini_profiler/storage/redis_store.rb

@@ -38,7 +38,7 @@ def get_unviewed_ids(user)
       def redis
         return @redis_connection if @redis_connection
         require 'redis' unless defined? Redis
-        Redis.new @args
+        @redis ||= Redis.new @args
       end
 
     end