Cannot migrate with foreign key in Laravel 5.2

I want to create two table users and roles. My codes are below:

2014_10_12_000000_create_users_table.php

<?php

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

class CreateUsersTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('users', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->integer('role')->unsigned();
            $table->string('email')->unique();
            $table->string('password');
            $table->rememberToken();
            $table->timestamps();

            $table->foreign('role')
                ->references('id')
                ->on('roles');
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('users');
    }
}

2016_03_09_004256_create_roles_table.php

<?php

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

class CreateRolesTable extends Migration
{
    /**
     * Run the migrations.
     *
     * @return void
     */
    public function up()
    {
        Schema::create('roles', function (Blueprint $table) {
            $table->increments('id');
            $table->string('name');
            $table->timestamps();
        });
    }

    /**
     * Reverse the migrations.
     *
     * @return void
     */
    public function down()
    {
        Schema::drop('roles');
    }
}

When I run php artisan migrate the following error appear.

[Illuminate\Database\QueryException] SQLSTATE[HY000]: General error: 1005 Can't create table trucking.#sql-1240_44 (errno: 150 "Foreign key constraint is incorrectly formed") (SQL: alter table users add constraint u sers_role_foreign foreign key (role) references roles (id))

[PDOException] SQLSTATE[HY000]: General error: 1005 Can't create table trucking.#sql-1240_44 (errno: 150 "Foreign key constraint is incorrectly formed")

via Chebli Mohamed