This is an easy fix. Use Bondo or any type of auto body filler to fill and repair the scratches. You will probably have to repaint the entire door. The repaired area could look different with the new paint. Fortunately, the steps are really easy to do.
1) Wash the door to remove dirt and oxidation. A mild dish soap and warm water should do the trick.
2) Lightly sand the scratched area with 120 grit sand paper. This will roughen up the area and remove any protruding paint edges.
3) Prime the area needing the repair with a good fast drying oil based primer. A spray can of Zinsser Cover Stain will work great.
4) Apply two thin coats of the auto body filler. Fill the area slightly higher than the surrounding area. Allow an hour for drying before proceeding.
5) Sand the area smooth and level with the surrounding door surfaces. Use 150 grit or finer sandpaper.
6) Now reprime the area with the same primer you used previously. The door is ready for repainting or try touching up the repaired area.