Add JSONB column support

[Krizz]

This pull request adds JSONB column type support.

[tyrauber]

@Krizz, do you remember why you closed this pull request? Seems to me jsonb column support instead of hstore columns would be very useful.

[Krizz]

@tyrauber Becuase the go.mod file was referencing my own repository and then I forgot about that pull request. Reopening it now.

[tyrauber]

@Krizz That'd be great! Native jsonb is definitely preferable to hstore IMO. Let me know if I can help in anyway.

[tyrauber]

@Krizz, Would you mind rebasing off master?

@olt, may we get eyes on this? It would be really nice to have jsonb as an option instead of hstore. JSONb doesn't require an extension, performs better and is easier to query for nested data.

Thank you @Krizz for opening this back up.