feat: Wiki の管理方法変更（#188） (#195)

Merge branch 'feature/188' of https://git.miteruzo.com/miteruzo/btrc-hub into feature/188

#188

Merge branch 'main' into feature/188

#188

#188

#188

#188

Co-authored-by: miteruzo <miteruzo@naver.com>
Reviewed-on: #195

backend/app/models/wiki_line.rb

@@ -0,0 +1,15 @@
+class WikiLine < ApplicationRecord
+  has_many :wiki_revision_lines, dependent: :restrict_with_exception
+
+  validates :sha256, presence: true, uniqueness: true, length: { is: 64 }
+  validates :body, presence: true
+
+  def self.upsert_by_body! body
+    sha = Digest::SHA256.hexdigest(body)
+    now = Time.current
+
+    upsert({ sha256: sha, body:, created_at: now, updated_at: now })
+
+    find_by!(sha256: sha)
+  end
+end