From https://laracasts.com/series/whats-new-in-laravel-5-1/episodes/16 - tested on version 5.6

AuthServiceProvider.php

<?php

namespace App\Providers;

use App\Permission;
use Illuminate\Support\Facades\Gate;
use Illuminate\Foundation\Support\Providers\AuthServiceProvider as ServiceProvider;

class AuthServiceProvider extends ServiceProvider
{
    /**
     * The policy mappings for the application.
     *
     * @var array
     */
    protected $policies = [
        'App\Model' => 'App\Policies\ModelPolicy',
    ];

    /**
     * Register any authentication / authorization services.
     *
     * @return void
     */
    public function boot()
    {
        $this->registerPolicies();

        foreach($this->getPermissions() as $permission){
            Gate::define($permission->name, function($user ) use ($permission){
                return $user->hasRole($permission->roles);
            });
        }       
    }
    protected function getPermissions(){
        return Permission::with('roles')->get();
    }
}

HasRoles.php

<?php

namespace App;

trait HasRoles
{

    /**
     * A user may have multiple roles.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }

    /**
     * Assign the given role to the user.
     *
     * @param  string $role
     * @return mixed
     */
    public function assignRole($role)
    {
        return $this->roles()->save(
            Role::whereName($role)->firstOrFail()
        );
    }

    /**
     * Determine if the user has the given role.
     *
     * @param  mixed $role
     * @return boolean
     */
    public function hasRole($role)
    {
        if (is_string($role)) {
            return $this->roles->contains('name', $role);
        }

        return !! $role->intersect($this->roles)->count();
    }

    /**
     * Determine if the user may perform the given permission.
     *
     * @param  Permission $permission
     * @return boolean
     */
    public function hasPermission(Permission $permission)
    {
        return $this->hasRole($permission->roles);
    }
}

Permission.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Permission extends Model
{
    /**
     * A permission can be applied to roles.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function roles()
    {
        return $this->belongsToMany(Role::class);
    }
}

Role.php

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class Role extends Model
{
    /**
     * A role may be given various permissions.
     *
     * @return \Illuminate\Database\Eloquent\Relations\BelongsToMany
     */
    public function permissions()
    {
        return $this->belongsToMany(Permission::class);
    }

    /**
     * Grant the given permission to a role.
     *
     * @param  Permission $permission
     * @return mixed
     */
    public function givePermissionTo(Permission $permission)
    {
        return $this->permissions()->save($permission);
    }
}

User.php

<?php

namespace App;

use Illuminate\Auth\Authenticatable;
use Illuminate\Database\Eloquent\Model;
use Illuminate\Auth\Passwords\CanResetPassword;
use Illuminate\Foundation\Auth\Access\Authorizable;
use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;
use Illuminate\Contracts\Auth\Access\Authorizable as AuthorizableContract;
use Illuminate\Contracts\Auth\CanResetPassword as CanResetPasswordContract;

class User extends Model implements AuthenticatableContract,
                                    AuthorizableContract,
                                    CanResetPasswordContract
{
    use Authenticatable, Authorizable, CanResetPassword, HasRoles;

    /**
     * The database table used by the model.
     *
     * @var string
     */
    protected $table = 'users';

    /**
     * The attributes that are mass assignable.
     *
     * @var array
     */
    protected $fillable = ['name', 'email', 'password'];

    /**
     * The attributes excluded from the model's JSON form.
     *
     * @var array
     */
    protected $hidden = ['password', 'remember_token'];

    public function roles(){
        return $this->belongsToMany(Role::class);
    }
    
    public function assingRole($role){
        return $this->roles()->save(
            Role::whereName($role)->firstOrFail()
        );
    }


    public function hasRole($role){
        if(is_string($role)){
            return $this->roles->contains('name', $role);
        }
        return !! $role->intersect($this->roles)->count();
        return false;
    }
}

web.php

<?php

Route::get('/', function () {
    Auth::loginUsingId(1);
    return view('welcome');
});

welcome.blade.php

<!DOCTYPE html>
<html>
    <head>
        <title>Laravel</title>

        <link href="https://fonts.googleapis.com/css?family=Lato:100" rel="stylesheet" type="text/css">
    </head>
    <body>
        <h1>Hello World</h1>

        <!-- Simulate various abilities. -->

        @can('edit_forum')
            <a href="#">Edit the Forum</a>
        @endcan

        @can('manage_money')
            <a href="#">Manage the Funds</a>
        @endcan
    </body>
</html>