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-396
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Cache-Control: max-age=0, no-cache, no-store, must-revalidate
Content-Type: application/json
Expires: Mon, 28 Sep 2020 06:22:52 GMT
Vary: Accept

{
    "count": 50,
    "next": null,
    "previous": null,
    "results": [
        {
            "source": "direct-sharing-396",
            "name": "AndroidAPS Uploader",
            "usernames": [
                "alternateal",
                "MarcelZ",
                "swissalpine",
                "AndyS",
                "Shaggydog",
                "TeleRiddler",
                "mogren",
                "quizzmaster",
                "markvader",
                "cristinav",
                "matnar",
                "Philoul",
                "Seveboru",
                "dlvoy",
                "overfrenk",
                "flea",
                "nehasvit",
                "chrisgruebl",
                "Standak",
                "wollek",
                "Snoopy913",
                "FreDiabetics",
                "RalfCGM",
                "Lew_Easy",
                "jonmcalroy",
                "guydavies",
                "Coeur",
                "aholareijo",
                "Jelmer",
                "D_Haak",
                "HermannW",
                "Tanja3981",
                "Loco_aleman",
                "ag_loompa",
                "Dave2526",
                "Stefanie22",
                "Charlyw76",
                "Heiner1",
                "MelC",
                "an_di",
                "WolfgangSpaenle",
                "alessiorosi",
                "JohnKitching",
                "Franzec",
                "martinchavdarov",
                "Bispham1983",
                "Pablo",
                "Konstantin37",
                "domswaine",
                "niko78",
                "zjed",
                "necargon",
                "Maren",
                "maireadyo",
                "Vickster",
                "cjlogan"
            ]
        }
    ]
}