Initial commit I think

Initial commit with just menu and sort of pause menu only

src/game/backend.rs

@@ -0,0 +1,53 @@
+extern crate rand;
+enum CellType {
+    Snake,
+    Food,
+    Empty,
+}
+struct Cell {
+    line: i32,
+    col: i32,
+    ctype: CellType,
+}
+
+impl Default for Cell {
+    fn default() -> Self {
+        Self {
+            line: -1,
+            col: -1,
+            ctype: CellType::Empty,
+        }
+    }
+}
+
+enum Direction {
+    Up,
+    Down,
+    Left,
+    Right,
+}
+struct Snake {
+    length: i32,
+}
+
+struct SnakeCell {
+    pub line: i32,
+    pub col: i32,
+}
+
+impl SnakeCell {
+    fn next(&self, direction: Direction) -> SnakeCell {
+        let (dl, dc) = match direction {
+            Direction::Up => (-1, 0),
+            Direction::Down => (1, 0),
+            Direction::Left => (0, -1),
+            Direction::Right => (0, 1),
+        };
+
+        SnakeCell {
+            line: self.line + dl,
+            col: self.col + dc,
+            // ctype: self.ctype,
+        }
+    }
+}