more questions about RoR!

is there something about garbage collection a rails application needs to
worry about? if models(i.e are being created eveytime a user
visits a page, does that memory get ‘held up’ some place? does it need

to be freed?

No, Ruby does garbage collection for you.

if there are multiple requests/updates to a table from multiple users,
does rails handle mutex/data protection? or is this not an issue?

Active Record supports both optimistic and pessimistic locking.

Add a lock_version integer not nil default 0 column to your table to automatically enable optimistic locking.