source_dict in data_blob.py

[ChrisAllisonMalta]

For a couple of reasons I've been writing an implementation of the data storage in SQL. I'm not sure if this is worth just a comment in the code or maybe its better in the documentation or even this note is ok?

What I discovered was that you need to have your data prefix ("sql") in the source_dict object on line 348 of the data_blob.py file otherwise the sim data won't now how to resolve db_futures_adjusted_prices_data into sqlFuturesAdjustedPricesData.

Seems obvious having written it but it stumped me for a while and hopefully helps someone in the future.

[robcarver17]

Might be worth documenting here