1.) Why would you want to? It's a web app.

2.) If you do want to:
Just follow the remastering guide:

mount /mnt/hda
cd /mnt/hda
mkdir source/KNOPPIX
mkdir master/KNOPPIX
cp -Cp /KNOPPIX source/KNOPPIX

Then add your app and database to the new uncompressed copy... removing other packages with apt-get if space becomes an issue.
After your done editing finishing the remastering with:

mkisofs -R -U -V "KNOPPIX.net filesystem" -publisher "KNOPPIX www.knoppix.net" \
-hide-rr-moved -cache-inodes -no-bak -pad /mnt/hda1/knx/source/KNOPPIX \
| nice -5 /usr/bin/create_compressed_fs - 65536 > /mnt/hda1/knx/master/KNOPPIX/KNOPPIX

and
cd /mnt/hda1/knx/master
find -type f -not -name md5sums -not -name boot.cat -not -name isolinux.bin \
-exec md5sum '{}' \; > KNOPPIX/md5sums

and then finally:
mkisofs -pad -l -r -J -v -V "KNOPPIX" -no-emul-boot -boot-load-size 4 \
-boot-info-table -b boot/isolinux/isolinux.bin -c boot/isolinux/boot.cat \
-hide-rr-moved -o /mnt/hda1/knx/knoppix.iso /mnt/hda1/knx/master

For more info, see:
http://www.knoppix.net/wiki/Knoppix_Remastering_Howto