Use dnf in fedora (fixes #20)

src/main.rs

@@ -147,9 +147,8 @@ fn main() -> Result<(), Error> {
             Ok(distribution) => {
                 match distribution {
                     linux::Distribution::Arch => upgrade_arch_linux(&sudo, &terminal),
-                    linux::Distribution::CentOS | linux::Distribution::Fedora => {
-                        upgrade_redhat(&sudo, &terminal)
-                    }
+                    linux::Distribution::CentOS => upgrade_redhat(&sudo, &terminal),
+                    linux::Distribution::Fedora => upgrade_fedora(&sudo, &terminal),
                     linux::Distribution::Ubuntu | linux::Distribution::Debian => {
                         upgrade_debian(&sudo, &terminal)
                     }

src/steps.rs

@@ -189,6 +189,23 @@ pub fn upgrade_redhat(
     Ok(())
 }
 
+pub fn upgrade_fedora(
+    sudo: &Result<PathBuf, which::Error>,
+    terminal: &Terminal,
+) -> Result<(), failure::Error> {
+    if let Ok(sudo) = &sudo {
+        Command::new(&sudo)
+            .args(&["dnf", "upgrade"])
+            .spawn()?
+            .wait()?
+            .check()?;
+    } else {
+        terminal.print_warning("No sudo detected. Skipping system upgrade");
+    }
+
+    Ok(())
+}
+
 pub fn upgrade_debian(
     sudo: &Result<PathBuf, which::Error>,
     terminal: &Terminal,