Updated some nameing to fit with the rest of the models

ref #37

src/seeds/SeedUsers.ts

@@ -29,7 +29,7 @@ export default class SeedUsers implements Seeder {
         initialUser.lastname = "demo";
         initialUser.username = "demo";
         initialUser.password = "demo";
-        initialUser.group = group;
+        initialUser.groups = group;
         return await connection.getRepository(User).save(await initialUser.toUser());
     }