remove redundant requirements.txt file
remove outdated data inputs
mysql backend schema revised to capture payload data
collapse type and namespace in one column in submission interest schema
replace manual database management with sqlalchemy
make sql database init script clearly marked
give SQLBackend a singleton creator
make internals of SQL backend more private-ish, add session property
improve submission model with indexing and columns to be timezone unaware, due to mysql
get_or_create for the User model
revamp SubmissionInterest table
ignore __news_counter and __news_home_counter interests in rankers
ingest script loads submissions and submission interests