--csv option for importing CSV

[simonw]

Right now CSV is handled by an obtuse recipe in https://github.com/simonw/git-history/blob/84663eeb60fc5f35f6845597d1cddb85e70b8f19/README.md#custom-conversions-using---convert

git-history file trees.db ../sf-tree-history/Street_Tree_List.csv \
  --repo ../sf-tree-history \
  --import csv \
  --import io \
  --convert 'list(csv.DictReader(io.StringIO(content.decode("utf-8"))))' \
  --id TreeID

This could and should be easier! Maybe a --csv option that does that for you?

[simonw]

I'm going to leave the example in the documentation but change it to use a different delimiter.

[simonw]

git-history file trees.db ../sf-tree-history/Street_Tree_List.csv \
  --repo ../sf-tree-history \
  --import csv \
  --import io \
  --convert 'list(csv.DictReader(io.StringIO(content.decode("utf-8"))), delimiter=";")' \
  --id TreeID