Adding a function to easily write teh character sheet.

src/sheet.rs

@@ -1,6 +1,7 @@
 use eframe::egui::widgets::DragValue;
 use eframe::egui::Ui;
 use serde::{Deserialize, Serialize};
+use std::io::Write as _;
 
 use crate::gui::SheetGui;
 
@@ -36,6 +37,12 @@ pub struct CharacterSheet {
     money: u32,
 }
 
+pub fn write_sheet(path: &std::path::Path, sheet: &CharacterSheet) -> std::io::Result<()> {
+    let sheet_str = serde_json::to_string_pretty(&sheet)?;
+    let mut file = std::fs::File::create(path)?;
+    write!(file, "{}", sheet_str)
+}
+
 impl CharacterSheet {
     pub fn character_class(&self) -> &Classe {
         &self.character_class