■ 参考
drag-n-drop in Vuetify — Part II - Vuetify - Medium
https://medium.com/vuetify/drag-n-drop-in-vuetify-part-ii-2b07b4b27684
SortableJS/Sortable
https://github.com/SortableJS/Sortable
Vuetify Simple tables
https://vuetifyjs.com/ja/components/simple-tables
■ 完成品
See the Pen Vuetify 2.x v-simple-table drag and drop by mykysyk (@mykysyk) on CodePen.