Current target is not specific enough

[smlbrd]

The current README sets the following target:

As a guideline, aim for at least 1-2 coins per theme over the course of your apprenticeship, choosing the ones most relevant to your project and interests.

A more concrete goal would give clearer structure to apprentices, and a scale (e.g. 15 is 'Pass', 20 is 'Merit' and 25+ is 'Distinction') may create clearer goals.

More stats required from current apprentices to gauge scales.