[feature request] support transactions for ORM

[nrempel]

There might be an argument against this, but it would be nice to be able to do something like:

const user = new User(); // Lucid model
user.first_name = 'Johnny'
user.last_name = 'Bravo'
user
  .transacting(trx) // a valid transaction reference
  .save()

[thetutlage]

#43

[thetutlage]

Closing since already implemented

[nrempel]

Thank you!