Write trades into a sql database

[nikhilsaraf]

Follow-up issues: #317 and #318

Desired Behavior

I want to be able to access all the trades executed by the bot in a database

Impact

The desired behavior will allow me to better work with kelp trades

Feature Suggestion

We can achieve the desired behavior by writing to the database as a fill tracking handler

References

depends on this bug: #193

Tasks

• port commits:
  • nikhilsaraf@0c9db72
  • nikhilsaraf@50fad16
  • nikhilsaraf@17402f4
  • nikhilsaraf@626580a
  • nikhilsaraf@4121ea8
  • nikhilsaraf@c11e700
• switch to a better db driver that can cross-compile, such as a postgres driver
• save asset issuers in db table (or foreign key to a markets table)
• use date types on date fields
• fix schema for trades table
• correct number of decimals for precision of float values
• composite primary key on trades table (market_id and txid)
• should provide a graceful failure mode experience when using without an installed postgres db, or one we cannot connect to
• add version number to the database and version numbers per table to know when they are upgraded (maybe in the same table with a column specifying table vs. db)

Testing

• test compiles and runs on local machine for local platform (OS, arch)

[nikhilsaraf]

needs CGO_ENABLED for sqlite to work for cross-compiling to linux
compiling directly on a linux system works without cgo enabled