Blender Cloth animation to Shape Keys

Software:
Blender 2.79

Steps for creating Shape Keys from cloth simulation: 

1. Create an object with Cloth simulation.
2. Give the Cloth Cache a name.
3. Set Cloth cache to Disk Cache.
4. Bake the Cloth animation.
5. Move the time slider to wanted cloth state.
6. Press the ‘Apply as Shape Key’ button on the Cloth modifier.
   * The cloth modifier will be deleted from the object.
   
7. Apply new cloth settings to the object.
8. Set Pinning to be the same Vertex Group if necessary.
9. Give Cloth Cache the same name as before.
10. Set Cloth cache to Disk Cache.
11. Play the animation timeline so that the cache frames on disk will be loaded again.
12. Repeat from step 5 for each cloth pose you want to turn to a shape key.