migrations/2016_01_01_000000_add_voyager_user_fields.php
public function up()
    {
        Schema::table('users', function ($table) {
            if (!Schema::hasColumn('users', 'avatar')) {
                $table->string('avatar')->nullable()->after('email')->default('users/default.png');
            }
            $table->bigInteger('role_id')->nullable()->after('id');
        });
    }
public function up()
    {
        Schema::table('users', function ($table) {
            if (!Schema::hasColumn('users', 'avatar')) {
                $table->string('avatar')->nullable()->after('email')->default('users/default.png');
            }
            $table->bigInteger('role_id')->nullable()->after('id');
        });
    }
Run the migrations.