add chat model

android/app/src/main/java/com/chatman/model/Chat.java

+package com.chatman.model;
+
+import java.util.Date;
+
+public class Chat {
+    private String idSender;
+    private String idReceiver;
+    private Date date;
+    private String message;
+
+    public Chat(String idSender, String idReceiver, Date date, String message) {
+        this.idSender = idSender;
+        this.idReceiver = idReceiver;
+        this.date = date;
+        this.message = message;
+    }
+
+    public String getIdSender() {
+        return idSender;
+    }
+
+    public void setIdSender(String idSender) {
+        this.idSender = idSender;
+    }
+
+    public String getIdReceiver() {
+        return idReceiver;
+    }
+
+    public void setIdReceiver(String idReceiver) {
+        this.idReceiver = idReceiver;
+    }
+
+    public Date getDate() {
+        return date;
+    }
+
+    public void setDate(Date date) {
+        this.date = date;
+    }
+
+    public String getMessage() {
+        return message;
+    }
+
+    public void setMessage(String message) {
+        this.message = message;
+    }
+}

android/app/src/main/java/com/chatman/model/ChatRoom.java

+package com.chatman.model;
+
+import java.util.List;
+
+public class ChatRoom {
+    private String idSender;
+    private List<Chat> messages;
+
+    public ChatRoom(String idSender, List<Chat> messages) {
+        this.idSender = idSender;
+        this.messages = messages;
+    }
+
+    public String getIdSender() {
+        return idSender;
+    }
+
+    public void setIdSender(String idSender) {
+        this.idSender = idSender;
+    }
+
+    public List<Chat> getMessages() {
+        return messages;
+    }
+
+    public void setMessages(List<Chat> messages) {
+        this.messages = messages;
+    }
+}