diff --git a/db/migrate/20200601113238_add_index_to_last_activity.rb b/db/migrate/20200601113238_add_index_to_last_activity.rb
new file mode 100644
index 0000000000000000000000000000000000000000..25d5948830aea02a8583287bcaac0eebe99773da
--- /dev/null
+++ b/db/migrate/20200601113238_add_index_to_last_activity.rb
@@ -0,0 +1,5 @@
+class AddIndexToLastActivity < ActiveRecord::Migration[5.2]
+  def change
+    add_index :posts, :last_activity
+  end
+end