add: provide more information on psql and redis connection errors

crates/core/src/database/drivers/postgres.rs

@@ -30,7 +30,7 @@ pub struct DataManager(
 impl DataManager {
     /// Obtain a connection to the staging database.
     pub(crate) async fn connect(&self) -> Result<Connection> {
-        Ok(self.3.get().await.unwrap())
+        Ok(self.3.get().await.expect("ERROR_TETRATTO_PSQL_CON"))
     }
 
     /// Create a new [`DataManager`] (and init database).