Delete unused files

...ublic/static/css/app.86a4513a3e04c0dcb73e6d6aea4580e4.css

...c/static/css/app.86a4513a3e04c0dcb73e6d6aea4580e4.css.map

backend/public/static/js/app.724f1ed0ea7a0263e71c.js

backend/public/static/js/app.724f1ed0ea7a0263e71c.js.map

backend/public/static/js/vendor.cb29043f681d8df309ac.js

backend/public/static/js/vendor.cb29043f681d8df309ac.js.map

backend/routes/index.js

backend/routes/users.js

frontend/src/components/BookIndexPage.vue

frontend/src/components/BookShowPage.vue

frontend/src/components/IndexPage.vue

view/buy.pug