Create customer key/value fields using the REST API

[JIrawl]

Hello, 

Is there a way to create customer with custom key/value fields in jiraservicedesk using the API ?

My current usage of the API is a shell script : 

curl --request POST \
--user 'admin':xxxxx \
--header 'Accept: application/json' \
--header 'Content-Type: application/json' \
--data '
{
"name": "'$email'",
"emailAddress": "'$email'",
"displayName": "'$displayname'",
"notification": "true",
"locale": "fr_FR"
}' \
--url 'http://localhost:8080/rest/api/latest/user' \
--silent

However, i need for this new user new fields like : 

- Title ( Mr or Mrs)

- Job

- Phone Number

- Company

- Other email

- etc

Is there a convenient way to do this using the REST API ? 

Thanks,