add gamemanager class and score

scripts/coin.gd

@@ -1,6 +1,7 @@
 extends Area2D
 
+@onready var game_manager: Node = %GameManager
 
 func _on_body_entered(_body: Node2D) -> void:
-	print("Plus 1 coin")
+	game_manager.add_point()
 	queue_free()

scripts/game_manager.gd

@@ -0,0 +1,9 @@
+extends Node
+
+var score = 0
+
+@onready var score_label: Label = $ScoreLabel
+
+func add_point():
+	score += 1
+	score_label.text = "You collected " + str(score) + " coins! :)"

scripts/game_manager.gd.uid

@@ -0,0 +1 @@
+uid://drwniyklox5wj