Please create a nowtz for working with Timestamptz

[lholden]

Due to a lack of implicit conversions currently if one wants to perform something such as

accessed_at.lt(now - 15.minutes())

Where accessed_at is a Timestamptz, one instead has to write:

accessed_at.lt(now.into_sql::<Timestamptz>() - 15.minutes())

Adding something like nowtz to the Diesel DSL would allow us to instead write:

accessed_at.lt(nowtz - 15.minutes())

[sgrif]

After implementing this, I'm not sure it really makes sense to have this in Diesel. The use case feels very niche, and not something that I think is worth maintaining in our own codebase -- Especially since you can have this in your own code base:

fn nowtz() -> AsExprOf<now, Timestamptz> {
    now.into_sql()
}

[berkus]

Ok, will add this to my codebase.. And probably many more will..

Is it possible to add this simple function in diesel just once instead?