Add sensitive words setting

app/models/admin/sensitive_word.rb

@@ -0,0 +1,25 @@
+# frozen_string_literal: true
+
+class Admin::SensitiveWord
+  class << self
+    def sensitive?(text, spoiler_text)
+      exposure_text = (spoiler_text.presence || text)
+      (spoiler_text.blank? && sensitive_words.any? { |word| text.include?(word) }) ||
+        sensitive_words_for_full.any? { |word| exposure_text.include?(word) }
+    end
+
+    def modified_text(text, spoiler_text)
+      spoiler_text.present? ? "#{spoiler_text}\n\n#{text}" : text
+    end
+
+    private
+
+    def sensitive_words
+      Setting.sensitive_words || []
+    end
+
+    def sensitive_words_for_full
+      Setting.sensitive_words_for_full || []
+    end
+  end
+end