Since you are making a hack, you are the only one who can make an ips patch by using the original and hacked rom. Once this is done, install the dropbox upload program. Then zip the ips, copy paste it into the dropbox system folder (the folder will be created upon install).
Wait for a while while the file is being auto-uploaded (green symbol appears in the icon). Now right click it and choose Share dropbox link. Go to regular txt editor and press paste. Now change the https into http since secured http is not implemented into romhacking.net yet.
A second thing you need to do is to change the www into dl. This will make a direct link! Only direct links to a zip/rar are acceptable at romhacking.net as url. I really don't know why dropbox has this strange default settings, since this is what we all want (a direct link).