Error: custom reponse error message

[Fangdun Tsai]

Examples:

• https://zeit.co/docs/api#api-basics/errors

  Struct:

  {
    "error": {
      "code": "forbidden",
      "message": "Not authorized"
    }
  }

• https://github.com/graphql/graphql-spec/blob/master/spec/Section%207%20--%20Response.md

• https://www.apollographql.com/docs/apollo-server/data/errors/

  Struct

  {
    "errors": [
      { "message": "" }
    ]
  }

[Fangdun Tsai]

https://github.com/rust-lang-nursery/failure

[Fangdun Tsai]

https://github.com/dtolnay/anyhow

[Fangdun Tsai]

Landed in 7137b9c.