add docs

Author: kewde

test/each.test.js

@@ -11,6 +11,8 @@ describe('each', function() {
         var total = 100000;
         var retrieved = 0;
 
+        // assert fails sometimes if previous test is still running & blocking.
+        // so wait until it is finished.
         db.wait(function() {
             db.each('SELECT id, txt FROM foo LIMIT 0, ?', total, function(err, row) {
                 if (err) throw err;