test passed for #birthday
added pry to Gemfile, passed test for #have_a_drink
updated some previous tests, and test passed for underage trying to drink
refactored test for 'have_a_drink' by creating new method to check age_at_least so i can also test 18
passed test for requiring person to be 18 to drive_a_car
test passed to prevent person over 21 with license to drive if also drunk
test passed for sober-up if user has had drinks
Test passed for not changing drinks attr when user has 0 drinks