Create a function that will return the average grade of a an array of students grades.
def average (grades)
grade.sum/grade.length
end# TODO: Replace examples and use TDD development by writing your own tests
# These are some of the methods available:
# Test.expect(boolean, [optional] message)
# Test.assert_equals(actual, expected, [optional] message)
# Test.assert_not_equals(actual, expected, [optional] message)