Create a mapping from a magic phrase to a secret. Retrieve it at /api/[phrase].
/api/[phrase]
/api/abcdefgh
curl /api/abcdefgh
/api/verysecret
curl /api/verysecret
/api/secret-magic-phrase
curl /api/secret-magic-phrase
/api/asecretroute
curl /api/asecretroute