Impl. duplicates identification

[dheshanm]

No description provided.

[dheshanm]

Proposed Schema:

Comments from Kevin:

1. Store history of file_path for local PHOENIX files Table
2. Add modality variable to file_mapping? eg) phone, interview, mri, eeg and others to the table?
3. Consider adding ID of RA who added each remote_file. How about we add more info to Remote_file table eg) owner, modifier, last_modified ?

[kcho]

Thanks for the commits! They look great. I'll see what I can do in sqlalchemy. I don't see the crawlers to add records to the db. Are we going to review the db models first before we work on crawlers?