Randomly select an avatar from id.

src/routes/users/get_avatar.rs

 use rocket::response::NamedFile;
 use std::path::Path;
 
-#[get("/<_target>/avatar")]
-pub async fn req(_target: String) -> Option<NamedFile> {
-    NamedFile::open(Path::new("avatar.png")).await.ok()
+use crate::database::Ref;
+
+#[get("/<target>/avatar")]
+pub async fn req(target: Ref) -> Option<NamedFile> {
+    match target.id.chars().nth(25).unwrap() {
+        '0' |
+        '1' |
+        '2' |
+        '3' |
+        '4' |
+        '5' |
+        '6' |
+        '7' => NamedFile::open(Path::new("assets/user_red.png")).await.ok(),
+        '8' |
+        '9' |
+        'A' |
+        'C' |
+        'B' |
+        'D' |
+        'E' |
+        'F' => NamedFile::open(Path::new("assets/user_green.png")).await.ok(),
+        'G' |
+        'H' |
+        'J' |
+        'K' |
+        'M' |
+        'N' |
+        'P' |
+        'Q' => NamedFile::open(Path::new("assets/user_blue.png")).await.ok(),
+        'R' |
+        'S' |
+        'T' |
+        'V' |
+        'W' |
+        'X' |
+        'Y' |
+        'Z' => NamedFile::open(Path::new("assets/user_yellow.png")).await.ok(),
+        _ => unreachable!()
+    }
 }