feat: add fetch builtin structure

src/builtins/fetch.rs

@@ -0,0 +1,11 @@
+use crate::error::ShellError;
+
+use super::{Builtin, BuiltinConfig};
+
+pub struct Fetch;
+
+impl Builtin for Fetch {
+    fn execute(&mut self, _: &mut BuiltinConfig, _: Vec<String>) -> Result<(), ShellError> {
+        Ok(())
+    }
+}

src/builtins/mod.rs

@@ -5,6 +5,7 @@ use once_cell::unsync::Lazy;
 mod cd;
 mod change_prompt;
 mod exit;
+mod fetch;
 mod open;
 mod pwd;
 
@@ -31,6 +32,7 @@ const BUILTINS: Lazy<Vec<(&str, Box<dyn Builtin>)>> = Lazy::new(|| {
         ("exit", Box::new(exit::Exit)),
         ("pwd", Box::new(pwd::Pwd)),
         ("open", Box::new(open::Open)),
+        ("fetch", Box::new(open::Open)),
     ]
 });