Remove extra generic

src/lib.rs

@@ -34,10 +34,9 @@ pub struct BlogDb {
 
 impl BlogDb {
     /// Create a new BlogDb with an initial user.
-    pub async fn new<S, T>(username: S, password: String) -> anyhow::Result<Self>
+    pub async fn new<S>(username: S, password: String) -> anyhow::Result<Self>
     where
         S: AsRef<str>,
-        T: AsRef<str>,
     {
         let main_db_name = dotenvy::var("DB_MAIN_PATH")?;
         let cache_name = dotenvy::var("DB_CACHE_PATH")?;