send content type on analyze module

closes #232

app/elastic/HTTPElasticClient.scala

@@ -211,13 +211,13 @@ class HTTPElasticClient @Inject()(client: WSClient) extends ElasticClient {
   def analyzeTextByField(index: String, field: String, text: String, target: ElasticServer) = {
     val path = s"/${encoded(index)}/_analyze"
     val body = Json.obj("text" -> text, "field" -> field).toString()
-    execute(path, "GET", Some(body), target)
+    execute(path, "GET", Some(body), target, Seq(JsonContentType))
   }
 
   def analyzeTextByAnalyzer(index: String, analyzer: String, text: String, target: ElasticServer) = {
     val path = s"/${encoded(index)}/_analyze"
     val body = Json.obj("text" -> text, "analyzer" -> analyzer).toString()
-    execute(path, "GET", Some(body), target)
+    execute(path, "GET", Some(body), target, Seq(JsonContentType))
   }
 
   def getClusterSettings(target: ElasticServer) = {