added color + changed flake.nix a little

src/main.rs

@@ -1,7 +1,10 @@
+use std::process;
+
 use crate::{
     providers::{Provider, github::Github},
     tui::user_select_repo,
 };
+use colored::*;
 use dialoguer::{Select, theme::ColorfulTheme};
 mod providers;
 mod tui;
@@ -32,9 +35,13 @@ async fn main() {
 
     let repos = gh.repositories().await.expect("Failed to get repos.");
 
-    let selection = user_select_repo(repos)
-        .await
-        .expect("Failed to select repository.");
+    let selection = match user_select_repo(repos).await {
+        Ok(r) => r,
+        Err(_) => {
+            println!("{}", "No repository was selected!".red());
+            process::exit(1);
+        }
+    };
 
     println!("{:#?}", selection);