Feauture request: Postgresql Identity column

[xorock]

As of Postgresql v10, in addition to standard sequences and serial type, there is also an identity column. Laravel has 2 methods for this:

->generatedAs($expression) | Create an identity column with specified sequence options (PostgreSQL)
-- | --
->always() | Defines the precedence of sequence values over input for an identity column (PostgreSQL)

Could You please add support for this feature?

[wolfy-j]

Sure, we will take a look at it with Large Postgres update which also going to include the schema support. No ETA yet, feel free to create PR.