Implement drive-thru contributors metric
Drive-thru contributors is a metric, defined (and explained) as follows:
When you go to a fast-food drive-thru, you show up, get what you need out of the transaction, and then leave to go about your life. The same is true of drive-thru contributors in FOSS projects. These people show up to the project, make a single contribution, and then leave, never to contribute there again. The majority of these contributions are “itch scratches”: the contributor has a bug they need fixed, a feature they need added, or just had a quick edit to make in the documentation. Once the contributor has solved their particular problem, they move on to continue what they were doing before.
The metric is explained in Drive-through contributors talk, by VM Brasseur.
We could implement it by bucketing contributions (eg, git commits) by author, and then selecting those with just one contribuiton, and counting them. More general, we could also show a bar chart with 1, 2-5, 6-15, >15 contributions (for example), which would be useful not only to know about drive-through contributors but also about contributors in other ranges.