A interval type for the postgres driver.
There is a separate document on how to contribute to this repo here
Rust-Postgres-Interval is dedicated datatype for the postgres interval type.
```rust extern crate pg_interval;
use pg_interval::Interval;
fn main() { let months = 13; let days = 1; let microseconds = 3600000000; let interval = Interval::new(months, days, microseconds); let output = interval.toiso8601(); assert_eq!(String::from("P1Y1M1DT1H"), output); } ```