Include a serde feature in the shared crate

board-shared/src/score.rs

@@ -14,14 +14,10 @@ fn calc_expression_score(tiles: &[Tile]) -> u32 {
     for token in tiles {
         match token {
             Tile::Digit(_) => digit_score += 1,
-            Tile::Operator(op) => {
-                match op {
-                    Operator::Add | Operator::Subtract => multiplier = 2,
-                    Operator::Multiply => multiplier = 3,
-                    Operator::Divide => digit_score += 10,
-                };
-            }
-            _ => unreachable!(),
+            Tile::Operator(Operator::Add | Operator::Subtract) => multiplier = 2,
+            Tile::Operator(Operator::Multiply) => multiplier = 3,
+            Tile::Operator(Operator::Divide) => digit_score += 10,
+            Tile::Equals => unreachable!(),
         }
     }
     digit_score * multiplier