+create table roles (
+ id INTEGER primary key autoincrement,
+ name TEXT,
+ system INTEGER default 0 not null
+);
+
+create table user_role (
+ id_user INTEGER,
+ id_role INTEGER,
+ FOREIGN KEY(id_user) REFERENCES users(id),
+ FOREIGN KEY(id_role) REFERENCES roles(id),
+ PRIMARY KEY(id_user, id_role)
+);
+