create projects using  vue-cli3.x  scaffolding 
 how can I use other UI frameworks or libraries in single-file vue components? 
 such as jQuery, Layui, Bootstrap. 
 I try to add a resource reference directly to  public/index.html , add the road strength prefix 
, and then bind the global variable to  Vue.prototype  in  main.js  and then use it in the vue single file component. Although it works, this should not be the correct way to use 
 and will report an error and warning every time it is compiled 
 look for other uses and find that they are all  vue-cli2.x  versions, which are realized by modifying the  webpack  configuration. The 
  vue-cli3.x  version of the document is not understood, ask for boss"s help! 

