initial data model implementation

db/migrate/20260122123828_create_comments.rb

@@ -0,0 +1,11 @@
+class CreateComments < ActiveRecord::Migration[8.1]
+  def change
+    create_table :comments do |t|
+      t.references :user, null: false, foreign_key: true
+      t.references :commentable, polymorphic: true, null: false
+      t.text :body, null: false
+
+      t.timestamps
+    end
+  end
+end