Separate library and binary crates

src/falling_sand/mod.rs

@@ -1,5 +1,5 @@
 mod element;
-mod rules;
+pub mod rules;
 mod systems;
 
 use bevy::{

src/lib.rs

@@ -0,0 +1,2 @@
+pub mod falling_sand;
+pub mod util;

src/main.rs

@@ -1,11 +1,9 @@
-mod falling_sand;
-mod util;
-
 use bevy::{
     diagnostic::{FrameTimeDiagnosticsPlugin, LogDiagnosticsPlugin},
     prelude::*,
     window::PresentMode,
 };
+use haranae_rs::falling_sand;
 
 fn main() {
     let window_plugin = WindowPlugin {