Right - assuming the question stays put 
You create a link in your snakes table to the users table, and you put the user object into that column.
So create a new column in “snakes” called “owner” and select link to table and choose Users.
Then when you create a new snake, do something like this :
me = anvil.users.get_user()
app_tables.snakes.add_row(name="python",owner=me)
Anvil maintains the link for you.