chore: Convert user emails to lowercase

packages/backend/src/db/migrations/20231013094544_convert_user_emails_to_lowercase.ts

@@ -0,0 +1,13 @@
+import { Knex } from 'knex';
+
+export async function up(knex: Knex): Promise<void> {
+  await knex('users')
+    .whereRaw('email != LOWER(email)')
+    .update({
+      email: knex.raw('LOWER(email)'),
+    });
+}
+
+export async function down(): Promise<void> {
+  // void
+}