[Feature request] Support for external storage on android

[Zeta]

Hi Matt,

Would it be possible to add support for external storage (e.g. an SD card) on android devices? Over the years, the total size of my write documents have grown to several gigabytes. Since the internal storage on my android tablet is tiny, I have to constantly move around documents from external to internal and vice versa. It would be really helpful to have Write support reading from/writing to external storage directly.

Highly appreciate your work on Write.

Thanks,

Zeta