#1 順番修正

backend/db/migrate/20250227211400_create_posts.rb

@@ -0,0 +1,12 @@
+class CreatePosts < ActiveRecord::Migration[7.0]
+  def change
+    create_table :posts do |t|
+      t.string :url, limit: 2000, null: false
+      t.string :thumbnail, limit: 255, null: false
+      t.string :thumbnail_base, limit: 2000, null: false
+      t.references :post, foreign_key: { to_table: :posts }
+      t.references :uploaded_by, foreign_key: { to_table: :users }
+      t.timestamps
+    end
+  end
+end