Add prepare script so it gets compiled

package.json

@@ -6,7 +6,8 @@
 	"types": "./@types/index.d.ts",
 	"scripts": {
 		"build": "tsc",
-		"watch": "npm run build -- --watch"
+		"watch": "npm run build -- --watch",
+		"prepare": "npm run build"
 	},
 	"author": "Kuba Orlik",
 	"license": "ISC",