in my web application i have 2 model as `month` and `lessons` that `month` is hasMany with `lessons`.

that means each lesson record belong to `month` table and each `month` hasMany `lesson`, now this is my models 

```
class Month extends Model
{
    protected $table = 'months';
    protected $guarded = ['id'];

    public function lessons()
    {
        return $this->hasMany(Lessons::class);
    }
}

class Lessons extends Model
{
    protected $table = 'section_lessons';
    protected $guarded = ['id'];

    public function month()
    {
        return $this->belongsTo(Month::class);
    }
}

```

now i'm trying to save simple record as relationship with this codes:

```
$month = new \App\Entities\Month;
$month->section_month_name = '';
$month->month_title = '';
$month->section_price = '';
$month->section_available = true;
$month->lessons_count = '';
$month->image = '';
//$month = $month->save();

$lesson = new \App\Entities\Lessons;
$lesson->title = '';
$lesson->content = '';
$lesson->file_url = '';
$lesson->filename = '';
$lesson->time = '';
$lesson->media = '';
$lesson->course = true;
//$lesson->save();

$month->lessons()->save($lesson);
$month->save();

```

i get this error:

```
SQLSTATE[42S22]: Column not found: 1054 Unknown column 'month_id' in 'field list' (SQL: insert into `section_lessons` (`title`, `content`, `file_url`, `filename`, `time`, `media`, `course`, `month_id`, `updated_at`, `created_at`)

```

Migration classes:

```
class Months extends Migration
{
    public function up()
    {
        Schema::create('months', function (Blueprint $table) {
            $table->increments('id');
            $table->string('section_month_name');
            $table->string('month_title');
            $table->string('section_price');
            $table->boolean('section_available');
            $table->integer('lessons_count');
            $table->text('image');
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('months');
    }
}

class Lessons extends Migration
{
    public function up()
    {
        Schema::create('section_lessons', function (Blueprint $table) {
            $table->increments('id');
            $table->integer('months_id')->unsigned();
            $table->foreign('months_id')->references('id')->on('months')->onDelete('cascade');
            $table->string('title');
            $table->string('content');
            $table->string('file_url');
            $table->string('filename');
            $table->string('time');
            $table->string('media');
            $table->boolean('course', false);
            $table->timestamps();
        });
    }

    public function down()
    {
        Schema::dropIfExists('section_lessons');
    }
}

```