Don’t need to return anything besides the token

app/initializers/custom-session.js

@@ -2,21 +2,32 @@
 import Ember from "ember";
 import Session from "simple-auth/session";
 
+// This is pulled straight from ember-cli-simple-auth-token
+function getTokenData(token) {
+  var tokenData = atob(token.split('.')[1]);
+  try {
+    return JSON.parse(tokenData);
+  } catch (e) {
+    return tokenData;
+  }
+}
+
 export default {
   name: "custom-session",
   before: "simple-auth",
   initialize: function(container) {
     Session.reopen({
       setCurrentUser: function() {
-        var id = this.get("user_id");
+        var token = this.get("token");
         var self = this;
 
-        if (!Ember.isEmpty(id)) {
-          return container.lookup("store:main").find("user", id).then(function(user) {
+        if (!Ember.isEmpty(token)) {
+          var t = getTokenData(token);
+          return container.lookup("store:main").find("user", t['sub']).then(function(user) {
             self.set("currentUser", user);
           });
         }
-      }.observes("user_id")
+      }.observes("token")
     });
   }
 };