increased the bulk cache limit to 500, it can be manually increased up to 1000 safely

lib/couchrest/core/database.rb

@@ -20,7 +20,7 @@ module CouchRest
       @uri = @root = "#{host}/#{name}"
       @streamer = Streamer.new(self)
       @bulk_save_cache = []
-      @bulk_save_cache_limit = 50
+      @bulk_save_cache_limit = 500  # must be smaller than the uuid count
     end
     
     # returns the database's uri