added stats model

app/src/main/java/com/wyattjmiller/tictactoeapp/Stats.kt

@@ -0,0 +1,23 @@
+package com.wyattjmiller.tictactoeapp
+
+class Stats {
+    private var mGamesPlayed: Int = 0
+    private var mGamesWonX: Int = 0
+    private var mGamesWonO: Int = 0
+    private var mGamePiecesPlaced: Int = 0
+
+    fun updateGamesPlayed() {
+        mGamesPlayed++
+    }
+
+    fun updateGamesWon(gameState: Gameboard.GameState) {
+        when (gameState) {
+            Gameboard.GameState.GamePlayerWinX -> mGamesWonX++
+            Gameboard.GameState.GamePlayerWinO -> mGamesWonO++
+        }
+    }
+
+    fun updatePiecePlaced() {
+        mGamePiecesPlaced++
+    }
+}