update sort alg of basic rater

lib/ranking/strategies/basic_rater.rb

 class Ranking::Strategies::BasicRater < Ranking::Strategy
 
   def sortByRate(items)
-    first = items.first
-    rest = items.drop(1)
-
-    rest.zip(rest.size.downto(1))
-        .collect { |item, reverseIndex| rateItem(item, reverseIndex) } # Returns RatedItem instance
-        .sort { |itemA, itemB| itemA.rate <=> itemB.rate }
+    items.zip( items.size.downto(1) )
+        .collect { |item,reverseIndex| self.rateItem( item, reverseIndex ) }
+        .sort { |itemA,itemB| itemA.rate <=> itemB.rate }
         .collect { |ri| ri.item }
-        .push(first)
         .reverse # Best ranked comes first
   end