updated makefile - create obj directory if it doesnt exist

Author: Driema

.gitignore

@@ -1,2 +1,3 @@
 ./obj
 ./main
+/SFML-2.5.1/*

makefile

@@ -1,6 +1,6 @@
 build: ./src/*.cpp
 	g++ -std=c++17 -c ./src/*.cpp
-	mv ./*.o ./obj
-	g++ ./obj/*.o -o main -lsfml-graphics -lsfml-window -lsfml-system 
+	mkdir -p obj && mv ./*.o ./obj
+	g++ ./obj/*.o -o main -lsfml-graphics -lsfml-window -lsfml-system
 	chmod 755 ./main
 	./main