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-206
HTTP 200 OK
Allow: GET, HEAD, OPTIONS
Cache-Control: max-age=0, no-cache, no-store, must-revalidate
Content-Type: application/json
Expires: Sun, 21 Jul 2019 06:48:16 GMT
Vary: Accept

{
    "count": 43,
    "next": null,
    "previous": null,
    "results": [
        {
            "source": "direct-sharing-206",
            "name": "nobism",
            "usernames": [
                "madprime",
                "gedankenstuecke",
                "nobismRogierKoning",
                "Johnnyharper",
                "Dharmit",
                "Pavia",
                "MarjoMontijn",
                "JST",
                "bright",
                "johnny062",
                "Valerian",
                "johnny46",
                "test_nobism",
                "nobism1",
                "usernobism",
                "testusr",
                "testnobismuser2",
                "johnnyy1ahoo",
                "testusernobism4",
                "testnobism",
                "testnobismuser5",
                "krinamodi",
                "testnobismuser6",
                "testusernobism8",
                "testusernobism20",
                "testusernobism30",
                "testusernobism40",
                "testusernobism50",
                "testusernobism24",
                "testusernobism2",
                "testusernobism34",
                "testusernobism11",
                "testnobismuser100",
                "nobismuser7",
                "johnnynobismuser",
                "nobismuser80",
                "nobismuserretesting2",
                "aanal",
                "nobismuser100",
                "flin1",
                "Vickyvm",
                "101FredGds",
                "Johnny_harper",
                "Jef",
                "Taylor55",
                "Claire",
                "Chapsy",
                "Deltaliam",
                "Vita2019",
                "Sammie",
                "Ilja",
                "PerkiePeter",
                "MacOssie",
                "johnnynobismuser35",
                "Testty",
                "Robin994",
                "Scapa",
                "Coples79",
                "johnnyharpernobismtesting1",
                "johnnyharpernobismtesting2",
                "Deedee",
                "Nienke1208",
                "Jamesmill1987",
                "ruth1304",
                "Foofan78",
                "Madsen",
                "Scott",
                "johnnyharpernobismtesting3",
                "Leticiasierra87",
                "Gjoviedo",
                "johnnyharpernobismtesting4",
                "johnnyharpernobismtesting5",
                "MafvanUtreg"
            ]
        }
    ]
}