Is it safer to have the salt in the source code? If the db gets compromised with salts then everything is lost.. but if they only have hashes they can't do anything with it.. If the salt is in the source code, you could use their userid or something else? anyone know..
Definitely use new salt for each password and store them in the database alongside the passwords. Please see https://en.wikipedia.org/wiki/Salt_(cryptography)#Common_mistakes for reasons. If you want to learn more about the topic, the whole wikipedia article is a great source, followed by https://en.wikipedia.org/wiki/Rainbow_table, maybe even some generic info about hashing like https://en.wikipedia.org/wiki/Cryptographic_hash_function.