Use temperature vector as segue to maps

[Robsteranium]

The vector exercise invites participants to make a vector of the high temperatures for the next 7 days, and use nth to extract the value for Tuesday.

Our group realised that they had differing interpretations of the base-day/ which ordinal value corresponded with Tuesday. This provided a nice segue into HashMaps and key-values pairs.

Perhaps this ought to be made explicit in the curriculum?

[Robsteranium]

This would also solve #18 as a byproduct.