fix: support loggers that don't implement addSerializers (such as pino) (#128)

Author: cprussin

lib/logHelpers.js

@@ -81,6 +81,9 @@ function child(name) {
  * @returns  {void}
  */
 function addSerializers(log) {
+    if (!log.addSerializers) {
+        return;
+    }
     log.addSerializers({
         conductorModel: function(model) {
             if (!model) {