Add support to send a message as a reply of another

Author: Thiago Moreira

src/main/java/com/whatsapp/api/domain/messages/Context.java

@@ -0,0 +1,18 @@
+package com.whatsapp.api.domain.messages;
+
+import com.fasterxml.jackson.annotation.JsonInclude;
+import com.fasterxml.jackson.annotation.JsonProperty;
+
+/**
+ * Object that allow messages to be replied
+ * 
+ * 
+ * @see <a href="https://developers.facebook.com/docs/whatsapp/cloud-api/guides/send-messages#replies">Replies</a>
+*/
+@JsonInclude(JsonInclude.Include.NON_NULL)
+public class Context {
+
+    @JsonProperty("message_id")
+    private String messageId;
+
+}

src/main/java/com/whatsapp/api/domain/messages/Message.java

@@ -17,6 +17,8 @@ public class Message {
     private final String messagingProduct = "whatsapp";
     @JsonProperty("recipient_type")
     private final String recipientType = "individual";
+    @JsonProperty("context")
+    private Context context;
     /**
      * The Interactive message.
      */