Fix example config and an unwrap in main()

Was panicking on missing cert file. Oops. Now prints an error like it
should

confetti.toml.example

@@ -19,5 +19,5 @@ admins = []
 url = "my.db.server"
 user = "confetti"
 password = "my_secret_password"
-db = "confetti"
+db_name = "confetti"
 num_connections = 8

src/main.rs

@@ -112,10 +112,23 @@ async fn main() -> ExitCode {
 
 
     // Read certificate file
-    let certs = CertificateDer::pem_file_iter(&config.certfile)
+    debug!("Reading certificate file");
-        .unwrap()
+    let certs = match CertificateDer::pem_file_iter(&config.certfile) {
-        .map(|cert| cert.unwrap())
+        Ok(certs) => match certs.collect::<Result<Vec<_>,_>>() {
-        .collect();
+            Ok(k) => k,
+            Err(e) => {
+                error!("Could not read certificates.");
+                error!("{}",e);
+                return ExitCode::FAILURE
+            }
+
+        },
+        Err(e) => {
+            error!("Could not read certificates.");
+            error!("{}",e);
+            return ExitCode::FAILURE
+        }
+    };
     let key = PrivateKeyDer::from_pem_file(&config.keyfile).unwrap();
 
     let address = match IpAddr::from_str(&config.listen_address) {