Update table and add data in a Laravel 5 Migration

Other answers are correct. But note that if you have a lot of records, updating all of them with ORM can take time. Use raw SQL queries to do that faster.

Schema::table('warrant_grants',function ($table){
        $table->string('name',100)->after('id')->nullable();
    });
DB::raw("UPDATE warrant_grants SET name=name+id");

The SQL query is not exact, and you have to make it for your own DB, but you get the point.

Based on this link i found the answer: https://stackoverflow.com/a/23506744/4650792

Schema::table('warrant_grants',function ($table){
        $table->string('name',100)->after('id')->nullable();
    });

    $results = DB::table('warrant_grants')->select('id','name')->get();

    $i = 1;
    foreach ($results as $result){
        DB::table('warrant_grants')
            ->where('id',$result->id)
            ->update([
                "name" => "Warrant-".$i
        ]);
        $i++;
    }

Thanks for the help anyway guys.