Return an array where each entry is an object with this form:

{ source: "fitbit", name: "Fitbit", usernames: ["beau", "madprime"] }

GET /api/public-data/members-by-source/?source=direct-sharing-252
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Cache-Control: max-age=0, no-cache, no-store, must-revalidate
Content-Type: application/json
Expires: Fri, 04 Dec 2020 10:48:00 GMT
Vary: Accept

{
    "count": 50,
    "next": null,
    "previous": null,
    "results": [
        {
            "source": "direct-sharing-252",
            "name": "nobism Ubiqum Cluster headache Project",
            "usernames": [
                "ramonimo",
                "benc",
                "taximeow",
                "bitsy",
                "nobismRogierKoning",
                "liubovv",
                "Sara",
                "jasteige",
                "MarjoMontijn",
                "JST",
                "bright",
                "Valerian",
                "101FredGds",
                "Romans8910",
                "Colinmunro3",
                "Deltaliam",
                "Ilja",
                "Coples79",
                "Joanfigueras",
                "sandiminar",
                "Deedee",
                "Jamesmill1987",
                "ruth1304",
                "Scott",
                "Leticiasierra87",
                "MafvanUtreg",
                "DBG",
                "Skrzyminski",
                "TDerksen",
                "Kanis",
                "Iraleksa",
                "Mtbadger",
                "MARK1983",
                "kmann21",
                "Annie",
                "RaptorX",
                "Nzleagle",
                "Keeps9478",
                "Raven",
                "Dlnmerced",
                "Hdj",
                "polbenedito",
                "FrankW",
                "Melis",
                "Jeffo",
                "Decash",
                "AbbyP",
                "ipveka",
                "Ingrid68",
                "Ryan473",
                "Sven",
                "hjderoo",
                "Scoutmaster",
                "mike1979",
                "Jess",
                "Dimmen",
                "Andrew1390"
            ]
        }
    ]
}