Change configuration schema

lua/cmp/menu.lua

@@ -105,7 +105,14 @@ menu.update = function(self, ctx, sources)
   end
 
   -- sort.
-  config.get().sorting.sort(entries)
+  table.sort(entries, function(e1, e2)
+    for _, fn in ipairs(config.get().sorting.comparators) do
+      local diff = fn(e1, e2)
+      if diff ~= nil then
+        return diff
+      end
+    end
+  end)
 
   -- create vim items.
   local items = {}