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-604
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Cache-Control: max-age=0, no-cache, no-store, must-revalidate
Content-Type: application/json
Expires: Wed, 22 Sep 2021 19:55:49 GMT
Vary: Accept

{
    "count": 53,
    "next": null,
    "previous": null,
    "results": [
        {
            "source": "direct-sharing-604",
            "name": "TeQfor1",
            "usernames": [
                "zreptil",
                "mistersauga",
                "chrisgruebl",
                "mohuma",
                "Tanja3981",
                "thseliger",
                "WolfgangSpaenle",
                "fabianbrueggemann",
                "Claudi",
                "jackjohnjeremy",
                "Klaus",
                "Monoid",
                "Dewlanna",
                "claudi111",
                "marcelb",
                "schilfbert",
                "akadiabetic",
                "Dani77",
                "AnneTrixi",
                "bianca_r",
                "suse",
                "Judith",
                "Penta",
                "MaeDiabetes",
                "DessertHunter",
                "CaroGo",
                "majong",
                "huckfin"
            ]
        }
    ]
}