diff --git a/.gitignore b/.gitignore
index bcceaa9..f67db4e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1,3 +1,4 @@
+.ruby-version
 .bundle/
 Gemfile.lock
 log/*.log
diff --git a/db/migrate/20220916174734_add_nonce_index_to_rails_lti2_provider_lti_launches.rb b/db/migrate/20220916174734_add_nonce_index_to_rails_lti2_provider_lti_launches.rb
new file mode 100644
index 0000000..7aa07fe
--- /dev/null
+++ b/db/migrate/20220916174734_add_nonce_index_to_rails_lti2_provider_lti_launches.rb
@@ -0,0 +1,7 @@
+# frozen_string_literal: true
+
+class AddNonceIndexToRailsLti2ProviderLtiLaunches < ActiveRecord::Migration[6.0]
+  def change
+    add_index('rails_lti2_provider_lti_launches', %w[nonce], name: 'index_launch_nonce', unique: true)
+  end
+end