don't panic on missing/invalid config file, try to be helpful instead

src/config.rs

@@ -1,19 +1,7 @@
-use std::fs::File;
-use std::io::prelude::*;
-
 pub const CLIENT_ID: &str = "d420a117a32841c2b3474932e49fb54b";
 
-#[derive(Serialize, Deserialize, Debug)]
+#[derive(Serialize, Deserialize, Debug, Default)]
 pub struct Config {
     pub username: String,
     pub password: String,
 }
-
-pub fn load(filename: &str) -> Result<Config, toml::de::Error> {
-    let mut f = File::open(filename).expect("ncspot configuration file not found");
-    let mut contents = String::new();
-    f.read_to_string(&mut contents)
-        .expect("something went wrong reading the file");
-
-    toml::from_str(&contents)
-}