solved build error

src/views/layouts/Index.js

@@ -0,0 +1 @@
+export {default as Tilebar} from './Tilebar.vue';

src/views/layouts/Tilebar.vue

@@ -0,0 +1,8 @@
+<template>
+    <div class="p-4">
+        <div class="container">
+            <router-view />
+        </div>
+    </div>
+</template>
+

src/views/muscles/Index.js

@@ -0,0 +1,6 @@
+export {default as Legs} from './Legs.vue';
+export {default as Back} from './Back.vue';
+export {default as Chest} from './Chest.vue';
+export {default as Shoulder} from './Shoulder.vue';
+export {default as Triceps} from './Triceps.vue';
+export {default as Biceps} from './Biceps.vue';