Essentially, I am having the same issue as this guy, minus the table prefix. Because I have no table prefix, his fix does not work. http://forums.laravel.com/viewtopic.php?i
You have to give the integer an unsigned flag in Laravel 5.4, like this:
public function up()
{
Schema::create('posts', function (Blueprint $table) {
$table->increments('post_id');
$table->text('title');
$table->text('text');
$table->integer('employee_post_id_number')->unsigned();
$table->foreign('employee_post_id_number')->references
('employee_id_number')->on('employees');
$table->timestamps();
});
}