getting error while inserting data to mysql database in laravel 5

My database is working fine with my laravel application but while i was trying to insert data to my database i am facing a error:

SQLSTATE[42S22]: Column not found: 1054 Unknown column 'updated_at' in 'field list' (SQL: insert intoarticles(article_head,article_body,updated_at,created_at) values (, , 2016-04-27 18:40:58, 2016-04-27 18:40:58))

My view file

`<form method="post" action="">
  {!! csrf_field() !!}
    <div class="form-group">
      <label for="write_heading">Write Heading:</label>
      <textarea class="form-control" rows="3" cols="10" id="write_heading" name="article_head" style="resize: none;"></textarea>
      <label for="write_post">Write Post:</label>
      <textarea class="form-control" rows="15" cols="10" id="write_post" name="article_body" placeholder="write something awesome!!" style="resize: none;"></textarea>
      <br>
      <div class="model-footer">
        <button type='submit' class='btn btn-primary create_button'>Create</button>
        <button type='reset' class='btn btn-default reset_button'>Reset</button>

        <button type="button" class="btn btn-danger close_button" data-dismiss="modal">Close</button>
      </div>

    </div>
</form>
`

my controller code

`class ArticleEditor extends Controller
{
    //insert article to database
    public function insert_article(Request $request) {

      $Article = new article;

      $Article->article_head = $request->article_head;
      $Article->article_body = $request->article_body;

      $Article->save();

      return redirect('/dashboard');
    }
}
`

Migration file

`   public function up()
    {
        Schema::create('articles', function(Blueprint $table)
        {
            $table->increments('article_id');
            $table->string('article_head', 500);
            $table->string('article_body', 10000);
            $table->dateTime('created_on');
        });
    }`

via Chebli Mohamed