add where clause

docs/docs/models-usage.md

@@ -540,7 +540,12 @@ This will produce an outer join. However, a `where` clause on a related model wi
 User.findAll({
   include: [
     {model: Tool, as: 'Instruments', include: [
-      {model: Teacher, include: [ /* etc */], required: false}
+      {
+      model: Teacher, 
+      where: {
+        school: "Woodstock Music School"
+      },
+      required: false}
     ]}
   ]
 }).then(function(users) {