docker build -t gringotts .

$ docker run --rm -it -v "$(pwd):/host" -w /host gringotts
Modified generator:
04bb3de13398a18e1c0d1a2d77ae8cbb9ea358d8c5c075eac51e0c408a0367db2ba187f1ab2febd8859d4c12811563fae6056fef803bff43964ca15c63a28cdc1fdfd38dab9fac20e7a8fa1fae619e576ee5706423414a3c3f8c7e1a2d8adc9cd7
Serializing root.txt and self-sign root certificate
Writing ca/root.pem
Serializing root private key
Writing ca/root-key.pem
read EC key
writing EC key
Generating a RSA private key
...............................................+++++
.........................................................................................+++++
writing new private key to 'ssl/server-key.pem'
-----
Using configuration from /usr/lib/ssl/openssl.cnf
Check that the request matches the signature
Signature ok
Certificate Details:
        Serial Number:
            7c:e6:11:18:1c:5a:14:3e:6f:f0:e2:85:ea:5f:c7:dc:50:a4:b9:b2
        Validity
            Not Before: Apr 30 00:00:00 2018 GMT
            Not After : Aug  1 00:00:00 2020 GMT
        Subject:
            countryName               = GB
            stateOrProvinceName       = Scotland
            localityName              = Highlands
            organizationName          = Gringotts
            organizationalUnitName    = Hogwarts Castle
            commonName                = hogwarts.lf.lc
        X509v3 extensions:
            X509v3 Subject Alternative Name:
                DNS:hogwarts.lf.lc
Certificate is to be certified until Aug  1 00:00:00 2020 GMT (184 days)

Write out database with 1 new entries
Data Base Updated
$ tree
.
├── ca
│   ├── root-key.pem
│   └── root.pem
└── ssl
    ├── server-bundle.pem
    ├── server-key.pem
    └── server.pem