User - Group relationship seems to be broken

[LiquidPL]

Disclaimer: I am a total Laravel noob ATM, so anything I say might be wrong.

While looking through the code, i noticed in App\Models\User.php:

...

    public function groups()
    {

        return $this->hasMany("App\Models\Group");
    }

...

and in App\Models\Group.php:

...

    public function users()
    {
        return $this->hasMany("App\Models\User");
    }

...

These method names suggest that this was meant to be a many-to-many relationship.

However, in Laravel docs it is stated that you need to implement it like this:

    // App/Models/User.php

    public function groups()
    {
        return $this->belongsToMany("App\Models\User");
    }    

    // App/Models/Group.php

    public function users()
    {
        return $this->belongsToMany("App\Models\Group");
    }

Right now, I can't seem to add an user to a group using the ORM (i succeeded in doing so by editing the database manually), and I can't add more than one user to a group.