DATASET: HFTF trained constituents

[alexander-griffen]

Fixes #162

[struan]

Looks good. I don't really understand the data given we are counting a group as 1 but also "one or more individuals" as the same. Possibly it's just the dataset name needs clarifying though?

[zarino]

ACTION: @alexander-griffen to seek advice on the difference between "groups" and "one or more individuals", from our resident HFTF expert @juliacush so we know whether the differentiate them in the dataset, or just treat them as the same thing.

[alexander-griffen]

From @juliacush:

I think group is formalised e.g. Transition Town Exeter, Friends of the Earth Sheffield, and one or more individuals is much more informal, just some people who might be friends/neighbours so the distinction might be meaningless to us!