This is how I initialize my parse server in my application

Application.kt

Parse.initialize(
   Parse.Configuration.Builder(this)
                .applicationId(Constant.APP_ID)
                .clientKey(null) // no client key needed in Parse open source
                .server(Constant.HOST) // http://talk.us-west-2.elasticbeanstalk.com/parse/
                .clientBuilder(builder)
                .build()
)

FirebaseInstanceId.getInstance().instanceId.addOnSuccessListener {
    val token = it.token
    if (token.isNotEmpty())
        Timber.tag(TAG).d(token)
}

val installation = ParseInstallation.getCurrentInstallation()
installation.put("user", "androuino")
installation.put("GCMSenderId", "myID")
installation.saveInBackground { e ->
    if (e == null)
        Timber.tag(TAG).d(installation.deviceToken)
    else
        Timber.tag(TAG).e(e)
}