feat(example): add example app and blog app with demos

examples/blog/db/migrate/20260828014505_create_posts.rb

@@ -0,0 +1,13 @@
+class CreatePosts < Prism::Orm::Migration
+  def up
+    create_table :posts do |t|
+      t.string :title
+      t.text :body
+      t.timestamps
+    end
+  end
+
+  def down
+    drop_table :posts
+  end
+end