relocating documents folder of ios applications
You can't access other folders beyond the sandbox from App Store applications.

There is a library in Cydia called Unbox that allows you to access the filesystem from a sandboxed application but you will need to create your own app to achieve this as it is NOT A TWEAK.

For Information, Sandboxing is Apple's security feature preventing App Store applications from accessing the whole filesystem and also limiting what API's can be used. Some private API's can, others will simply crash if run in the Sandbox.