ruby: add comment from triage session

Author: yoff

ruby/ql/src/queries/performance/CouldBeAsync.ql

@@ -8,6 +8,12 @@
  * @tags performance
  */
 
+// Consider also Associations.
+// Associations are lazy-loading by default, so something like
+// in a loop over article do
+//    article.book
+// if you have 1000 articles it will do a 1000 calls to book.
+// If you already did article includes book, there should be no problem.
 import ruby
 private import codeql.ruby.AST
 import codeql.ruby.Concepts