Add constraints that are in the production DB (#14225)

* Add constraints that are in the production DB

* Nudge CI

db/schema.rb

@@ -14,6 +14,7 @@ ActiveRecord::Schema.define(version: 2021_06_29_174206) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "citext"
+  enable_extension "pg_stat_statements"
   enable_extension "pg_trgm"
   enable_extension "pgcrypto"
   enable_extension "plpgsql"
@@ -1439,9 +1440,9 @@ ActiveRecord::Schema.define(version: 2021_06_29_174206) do
 
   create_table "users_gdpr_delete_requests", force: :cascade do |t|
     t.datetime "created_at", precision: 6, null: false
-    t.string "email"
+    t.string "email", null: false
     t.datetime "updated_at", precision: 6, null: false
-    t.integer "user_id"
+    t.integer "user_id", null: false
     t.string "username"
   end