Add ChatRoomActivity.kt

app/src/main/java/chat/rocket/android/app/ChatRoomActivity.kt

+package chat.rocket.android.app
+
+import android.os.Bundle
+import chat.rocket.android.BaseActivity
+import chat.rocket.android.R
+import chat.rocket.android.app.chatroom.MessageFragment
+
+class ChatRoomActivity : BaseActivity() {
+
+    override fun onCreate(savedInstanceState: Bundle?) {
+        super.onCreate(savedInstanceState)
+        setContentView(R.layout.activity_chat_room)
+
+        addFragment(MessageFragment(), "MessageFragment", R.id.fragment_container)
+    }
+}
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