Add activity_room.xml

app/src/main/res/layout/activity_room.xml

+<?xml version="1.0" encoding="utf-8"?>
+<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
+    xmlns:app="http://schemas.android.com/apk/res-auto"
+    xmlns:tools="http://schemas.android.com/tools"
+    android:layout_width="match_parent"
+    android:layout_height="match_parent"
+    android:orientation="vertical"
+    tools:context="chat.rocket.android.activity.room.RoomActivity">
+
+    <android.support.design.widget.AppBarLayout
+        android:layout_width="match_parent"
+        android:layout_height="wrap_content">
+
+        <android.support.v7.widget.Toolbar
+            android:id="@+id/toolbar"
+            android:layout_width="match_parent"
+            android:layout_height="?attr/actionBarSize"
+            app:theme="@style/ThemeOverlay.AppCompat.Dark.ActionBar"
+            app:popupTheme="@style/ThemeOverlay.AppCompat.Light" />
+    </android.support.design.widget.AppBarLayout>
+
+    <FrameLayout
+        android:id="@+id/fragment_container"
+        android:layout_width="match_parent"
+        android:layout_height="match_parent" />
+</LinearLayout>
\ No newline at end of file