refactor: Update app.vue to include GitHub login button

TODO
- Add GitHub Authentication
- Show Error Messages on Front-end

app.vue

@@ -19,12 +19,12 @@
             <NuxtLink to="/">東雲文庫/Shinonome Bunko (Preview)</NuxtLink>
           </v-app-bar-title>
           <v-spacer />
+          <v-btn>Login with GitHub</v-btn>
           <v-btn
             href="https://github.com/itsukikigoshi/shinonome-bunko"
             icon="mdi-github"
             target="_blank"
           ></v-btn>
-          <v-btn>Login with GitHub</v-btn>
         </v-app-bar>
         <v-main>
           <NuxtPage />