add route for update usefulness

[wagaru]

👏 解決掉的 issue / Resolved Issues

• close #230

📝 相關的 issue / Related Issues

• 230

• 210

⛏ 變更內容 / Details of Changes

• 因為 API endpoint 仍使用文章推文，所以沒有新增 route，而是使用原本的 delivery.appendComment
• 如果 type 是 ↑ 或 ↓，則 text 可以為空
• 如果是上下箭頭推文則呼叫 usecase.UpdateUsefulness

目前程式直接判斷 appendType == "↑"，有需改成用 unicode 表示嗎？像是 appendType == "\u2191"

[codecov-commenter]

Codecov Report

Merging #234 (2376653) into development (84585bf) will increase coverage by 0.44%. The diff coverage is 91.30%.

@@               Coverage Diff               @@
##           development     #234      +/-   ##
===============================================
+ Coverage        47.67%   48.11%   +0.44%     
===============================================
  Files               28       28              
  Lines             1422     1436      +14     
===============================================
+ Hits               678      691      +13     
- Misses             647      648       +1     
  Partials            97       97              

Impacted Files	Coverage Δ
internal/usecase/article.go	28.20% <0.00%> (-0.75%)	:arrow_down:
internal/usecase/usecase.go	100.00% <ø> (ø)
internal/delivery/http/route_append_comment.go	79.10% <95.45%> (+5.03%)	:arrow_up:

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[PichuChen]

用 \x 的hex表示可讀性會比較低，也比較可能出錯，未來方向可能有兩種，另外一種是用變數來代表，另一種是寫到設定檔裡

[y2468101216]

LGTM