Split dashboard into home page and battery list page

templates/battery_add.html

@@ -97,7 +97,7 @@
 
     <div class="form-actions">
       <button class="btn btn-primary" type="submit">Add Batteries</button>
-      <a class="btn btn-secondary" href="{{ url_for('dashboard') }}">Cancel</a>
+      <a class="btn btn-secondary" href="{{ url_for('battery_list') }}">Cancel</a>
     </div>
   </form>
 </div>