Update Request to sites.json

I added runtastic.com to your list this is what i put  and i like your site it helps me allot thx
        "name": "Runtastic",
        "url": "https://help.runtastic.com/hc/en-us/articles/200370082-Delete-Account-Cancel-Membership",
        "difficulty": "easy",
        "notes": "To delete your account go to Runtastic.com & log in, click on the arrow on the right side of your user name, click on "Settings", click on "Login Data" on the left hand side, click on "Delete my account" at the bottom",
        "domains": [
            "runtastic.com"
        ]