list traction and add leaderboard panel

lib/main.dart

@@ -1,5 +1,6 @@
 import 'package:flutter/material.dart';
 import 'package:dynamic_color/dynamic_color.dart';
+import 'package:mileograph_flutter/components/pages/traction.dart';
 import 'package:provider/provider.dart';
 
 import 'package:mileograph_flutter/components/pages/legs.dart';
@@ -125,7 +126,7 @@ class _MyHomePageState extends State<MyHomePage> {
     Dashboard(),
     Center(child: Text("Calculator Page")),
     LegsPage(),
-    Center(child: Text("Traction Page")),
+    TractionPage(),
     Center(child: Text("Trips Page")),
   ];
 
@@ -148,6 +149,9 @@ class _MyHomePageState extends State<MyHomePage> {
         if (data.legs.isEmpty) {
           data.fetchLegs();
         }
+        if (data.traction.isEmpty) {
+          data.fetchHadTraction();
+        }
       });
     }
   }
@@ -162,12 +166,7 @@ class _MyHomePageState extends State<MyHomePage> {
     if (data.homepageStats != null) {
       currentPage = contentPages[pageIndex];
     } else {
-      currentPage = Center(
-        child: FilledButton(
-          onPressed: data.fetchHomepageStats,
-          child: CircularProgressIndicator(),
-        ),
-      );
+      currentPage = Center(child: CircularProgressIndicator());
     }
     // This method is rerun every time setState is called, for instance as done
     // by the _incrementCounter method above.