react-rust-postgres: add connection to postgres with migrations

Signed-off-by: Jérémie Drouet <jeremie.drouet@gmail.com>

react-rust-postgres/backend/src/user.rs

@@ -0,0 +1,18 @@
+#![allow(proc_macro_derive_resolution_fallback)]
+
+use diesel;
+use diesel::prelude::*;
+use super::schema::users;
+
+#[derive(Queryable, AsChangeset, Serialize, Deserialize)]
+#[table_name = "users"]
+pub struct User {
+    pub id: i32,
+    pub login: String,
+}
+
+impl User {
+    pub fn all(connection: &PgConnection) -> QueryResult<Vec<User>> {
+        users::table.load::<User>(&*connection)
+    }
+}