Update SUMMARY with current reference APIs. (#507)

docs/reference/game/add-score.md

@@ -0,0 +1,30 @@
+# add Score
+
+Add more to the current score for the game.
+
+```sig
+game.addScore(1)
+```
+### Parameters
+
+* a [number](/types/number) that means how much to add to the score. A negative number means to subtract from the score.
+
+### Examples
+
+This program is a simple game.
+Press button ``A`` as much as possible to increase the score. 
+Press ``B`` to display the score and reset the score.
+
+```blocks
+input.onButtonPressed(Button.B, () => {
+    basic.showNumber(game.score())
+    game.setScore(0)
+})
+input.onButtonPressed(Button.A, () => {
+    game.addScore(1)
+})
+```
+
+### See Also
+
+[score](/reference/game/score), [set score](/reference/game/set-score), [start countdown](/reference/game/start-countdown)