Laravel - Laracasts

I am a nube to Laravel and I tryed erally hard to figure out where the issue is but cant seems to find it. Thanks in advance to everyone..

This is the error: SQLSTATE[23000]: Integrity constraint violation: 1452 Cannot add or update a child row: a foreign key constraint fails (homestead.articles_tag, CONSTRAINT articles_tag_tag_id_foreign FOREIGN KEY (tag_id) REFERENCES tags (id) ON DELETE CASCADE) (SQL: insert into articles_tag (articles_id, created_at, tag_id, updated_at) values (4, 2015-10-05 09:33:18, 0, 2015-10-05 09:33:18))

This is the Tag eloquent model:

namespace App;

use Illuminate\Database\Eloquent\Model;

class Tag extends Model { protected $fillable = array();

//get the articles associated with the given tag
public function articles(){
    return $this->belongsToMany('App/Article');
} 

}

This is the Articles eloquent model:

namespace App;

use Illuminate\Database\Eloquent\Model; use Carbon\Carbon;

class Articles extends Model { protected $fillable = [ 'title', 'body', 'published_at', 'user_id' ];

protected $dates = ['published_at'];

public function scopePublished($query){
    $query->where('published_at', '<=', Carbon::now());
}

public function scopeUnpublished($query){
    $query->where('published_at', '>', Carbon::now());
}

public function setPublishedAtAttribute($date){
    $this->attributes['published_at'] = Carbon::parse($date);
}

//An article is owned by a user
public function user(){
    return $this->belongsTo('App\User');
}

//An article has many tags
//get the tags associated with the tables
public function tags(){
    return $this->belongsToMany('App\Tag')->withTimestamps(); 
}

/*
public function setPasswordAttribute($password){
    $this->attributes['password'] = mcrypt($password);
} //key is to user attributes
*/

}

This is my db schema:

use Illuminate\Database\Schema\Blueprint; use Illuminate\Database\Migrations\Migration;

class CreateTagsTable extends Migration {

public function up()
{
    Schema::create('tags', function (Blueprint $table) {
        $table->increments('id');
        $table->string('name');
        $table->timestamps();
    });

    //we are trying to connect articles and tags
    //really it sould we article_tag not articles_tag ;)
    Schema::create('articles_tag', function (Blueprint $table) {
        $table->integer('articles_id')->unsigned()->index();
        $table->foreign('articles_id')->references('id')->on('articles')->onDelete('cascade');

        $table->integer('tag_id')->unsigned()->index();
        $table->foreign('tag_id')->references('id')->on('tags')->onDelete('cascade');

        $table->timestamps();
    });
}


public function down()
{
    Schema::drop('tags');
    Schema::drop('articles_id');
}

}

this is is articels schema :

use Illuminate\Database\Schema\Blueprint; use Illuminate\Database\Migrations\Migration;

class Articles extends Migration {

public function up()
{
    Schema::create('articles', function(Blueprint $table){
        $table->increments('id');
        $table->integer('user_id')->unsigned();
        $table->string('title');
        $table->text('body');
        $table->timestamps();
        $table->timestamp('published_at');

        $table->foreign('user_id')
              ->references('id')
              ->on('users')
              ->onDelete('cascade');
    });
}

public function down()
{
    Schema::drop('articles');
}

}

via Chebli Mohamed