add ecs architecture

rusty-roguelike/src/systems/mod.rs

@@ -0,0 +1,13 @@
+mod player_input;
+mod map_render;
+mod entity_render;
+
+pub use crate::prelude::*;
+
+pub fn build_scheduler() -> Schedule {
+    return Schedule::builder()
+        .add_system(player_input::player_input_system())
+        .add_system(map_render::map_render_system())
+        .add_system(entity_render::entity_render_system())
+        .build();
+}