Need help on LTR

[Amjad Khan]

I followed the Solr LTR Documentation 

https://lucene.apache.org/solr/guide/7_4/learning-to-rank.html 
<https://lucene.apache.org/solr/guide/7_4/learning-to-rank.html>

1. Added library into the solr-config
<!--LTR Start-->
  <lib dir="${solr.install.dir:../../../..}/contrib/ltr/lib/" regex=".*\.jar" />
<lib dir="${solr.install.dir:../../../..}/dist/" regex="solr-ltr-\d.*\.jar" />
2. Successfully added feature
3. Get schema to see feature is available
4. When I try to push model I see the error below, however I added the lib into 
solr-cofig

Response
{
  "responseHeader":{
    "status":400,
    "QTime":1},
  "error":{
    "metadata":[
      "error-class","org.apache.solr.common.SolrException",
      "root-error-class","java.lang.NullPointerException"],
    "msg":"org.apache.solr.ltr.model.ModelException: Model type does not exist 
org.apache.solr.ltr.model.LinearModel",
    "code":400}}

Thanks