Decide the error format of API

[chimame]

Problems and suggestions:問題・課題点/提案

In the case of an error, since the JSON format is not fixed, it is difficult to use for the client. ex.

1. Response at mandatory error when posting to /communities.

   {
     "description": [
       "を入力してください"
     ]
   }

2. Response at the time of NotFound error when getting to /communities/0.

   {"status":404,"error":"Not Found"}

   Countermeasure:対応方法（案）

   I considered the following format. What do you think.

   {
   "level": 1,#1=warning, 2=error
   "messages": [] #I am considering entering multiple messages.
   }

[ytorii]

I thought case 1 corresponds to level 1(warning) and case 2 corresponds to level 2(error), is that correct? If possible, I think the format of RFC 7807 is worthy of consideration. https://www.eisbahn.jp/yoichiro/2017/01/rfc_7807.html

[springaki]

@chimame @ytorii これはどうなるの？

[chimame]

これは置いておいてもらっていいですか？

[springaki]

はーい