fix crash when using RustAppBuilder

Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name = "spl"
-version = "0.1.0"
+version = "0.1.1"
 edition = "2021"
 description = "Stack Pogramming Language: A simple, concise scripting language."
 license = "MIT"

src/oxidizer/mod.rs

@@ -61,8 +61,10 @@ impl Hash for RustAppBuilder {
 impl RustAppBuilder {
     pub fn new() -> RustAppBuilder {
         Self {
+            rust_functions: Vec::new(),
+            to_embed: HashMap::new(),
             default_file: "repl.spl".to_owned(),
-            ..Default::default()
+            name: None,
         }
     }