Modify how test output is saved.

Jenkinsfile

@@ -17,7 +17,9 @@ mix compile'''
       steps {
         sh '''mix ecto.create
 mix ecto.migrate
-mix coveralls --trace --preload-modules'''
+mix coveralls.html --trace --preload-modules'''
+        junit '_build/pleroma-junit.xml'
+        archiveArtifacts(artifacts: 'cover/excoveralls.html', allowEmptyArchive: true)
       }
     }
     stage('Analysis') {
@@ -34,11 +36,6 @@ mix coveralls --trace --preload-modules'''
         }
       }
     }
-    stage('Save') {
-      steps {
-        junit '_build/pleroma-junit.xml'
-      }
-    }
   }
   environment {
     MIX_ENV = 'test'