Added serialization.
Added serialization.

cornelltech/ResearchKit,chb/ResearchKit,jimmyti/ResearchKit,YuanZhu-apple/ResearchKit,oliverschaefer/ResearchKit,allen7wang/ResearchKit,md0u80c9/ResearchKit,boland25/ResearchKit,oliverschaefer/ResearchKit,boland25/ResearchKit,jarrelscy/ResearchKit,YuanZhu-apple/ResearchKit,md0u80c9/ResearchKit,jeremiahyan/ResearchKit,danoli3/ResearchKit,jarrelscy/ResearchKit,danoli3/ResearchKit,chb/ResearchKit,weijentu/ResearchKit,boland25/ResearchKit,mluedke2/ResearchKit,KaiCode2/ResearchKit,shazino/ResearchKit,weijentu/ResearchKit,chb/ResearchKit,jimmyti/ResearchKit,mluedke2/ResearchKit,umerkhan-apple/ResearchKit,jimmyti/ResearchKit,jarrelscy/ResearchKit,boland25/ResearchKit,umerkhan-apple/ResearchKit,jeremiahyan/ResearchKit,umerkhan-apple/ResearchKit,cornelltech/ResearchKit,KaiCode2/ResearchKit,oliverschaefer/ResearchKit,shazino/ResearchKit,mluedke2/ResearchKit,oliverschaefer/ResearchKit,KaiCode2/ResearchKit,cornelltech/ResearchKit,chb/ResearchKit,allen7wang/ResearchKit,allen7wang/ResearchKit,QuintilesRK/ResearchKit,md0u80c9/ResearchKit,md0u80c9/ResearchKit,weijentu/ResearchKit,YuanZhu-apple/ResearchKit,jeremiahyan/ResearchKit,danoli3/ResearchKit,YuanZhu-apple/ResearchKit,QuintilesRK/ResearchKit,QuintilesRK/ResearchKit,shazino/ResearchKit,weijentu/ResearchKit