some comments

src/id.rs

@@ -1,3 +1,7 @@
+//! Universally unique identifier
+//!
+//! Wrapper around `Uuid` to store it as text in sql table.
+
 use std::cmp::{Eq, PartialEq};
 use std::fmt;
 use std::hash::{Hash, Hasher};
@@ -6,10 +10,12 @@ use rusqlite::types::{FromSql, FromSqlError, FromSqlResult, ToSql, ToSqlOutput,
 use serde::{Deserialize, Serialize};
 use uuid::Uuid;
 
+/// Universally unique identifier
 #[derive(Clone, Copy, Debug, Deserialize, Serialize)]
 pub struct Id(Uuid);
 
 impl Id {
+	/// Return a newly generated `Id`
 	pub fn new() -> Self {
 		Self(Uuid::new_v4())
 	}