Go into lib/app_name_web/endpoint.ex
and look for
plug Plug.Static,
at: "/", from: :jslib, gzip: false,
only: ~w(css fonts images js favicon.ico robots.txt)
and add the new folder a
to the others
plug Plug.Static,
at: "/", from: :jslib, gzip: false,
only: ~w(a css fonts images js favicon.ico robots.txt)
https://til.hashrocket.com/posts/1a3639476e-serve-static-filesdirectories-in-phoenix