Update DB Schema to include additional tables and stream for nearby stations and discount

Changed the data type of current_discount in StationStatus to Integer instead of
Float as it is a count rather than the actual value.
Added s1 stream to hold the cascade user_id from the bikeStatus stream.
Added nearByStations and nearByDiscounts tables.  The nearByStation is to hold the last N
near by stations for a given user.  The nearByDiscount is to hold the last N stations with
available discounts.
Implemented BikeStatusTrigger as VoltProcedure
This VoltProcedure will trigger on INSERT INTO bikeStatus STREAM and performs the following tasks;
  a.  Replaces the TOP N near by stations for a given user in the nearByStations TABLE
  b.  Feeds the user_id to the s1 STREAM.
Implemented S1Trigger as VoltProcedure

This VoltProcedure will trigger on INSERT INTO s1 STREAM and performs the following;
 a. Replaces the near by stations that offer discount for a given user in the nearByDiscounts TABLE