Additional instructions to use cs50

Makefile

# You can download cs50 library from https://manual.cs50.net/library/#mac_os_2 and follow the instructions to download.
# You will have to manually link (`-I /usr/local/include -L /usr/local/lib -lcs50 -lm` for the linking step of compilation to work)
# to the 'include' and 'lib' directories in your makefiles if you want to use the cs50 library.
#
# Makefile
#
# Computer Science 50
# Problem Set 3
#
# Example Makefile for Problem Set 3 below

fifteen: fifteen.c
	clang -ggdb3 -O0 -std=c11 -Wall -Werror -o fifteen fifteen.c -I /usr/local/include -L /usr/local/lib -lcs50 -lm

clean:
	rm -f *.o a.out core fifteen log.txt