adding the instructions to run in a README file

assn3/README

+The command line utility cddb can be run as:
+
+./cddb [options]
+
+only 1 option can be run at a time, as they would have conflict if run ultiple at same time
+Does not need any argument except for the environment variable $CDDB
+
+Remember to set: export CDDB='$PATH'
+before running the utility
+
+after running the utility, the source code can be viewed by : make view
+and the temporary files can be cleaned by: make clean