Fixed missing packages and database

api/database.sql

@@ -16,10 +16,5 @@ CREATE TABLE users (
   password VARCHAR(255) NOT NULL,
   score INT UNSIGNED NOT NULL DEFAULT 0,
   PRIMARY KEY (id),
-  CONSTRAINT u_user_type_id
+  INDEX ur_username_idx (username)
-    FOREIGN KEY (user_type_id)
-    REFERENCES user_types(id)
-    ON DELETE RESTRICT
-    ON UPDATE CASCADE,
-  INDEX ur_user_type_idx (user_type_id)
 ) ENGINE=InnoDB;