You need to specify an extensions file.
For example:
openssl x509 -days 365 -in myCSR.csr -extfile v3.ext -CA myCA.crt -CAkey myCA.key -CAcreateserial -out userCertificate.crt
The extensions file (v3.ext) can look like this:
authorityKeyIdentifier=keyid,issuer
basicConstraints=CA:FALSE
keyUsage = digitalSignature, nonRepudiation, keyEncipherment, dataEncipherment