leaderboard.xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    xmlns:app="http://schemas.android.com/apk/res-auto">

    <android.support.v7.widget.Toolbar
        android:id="@+id/toolbar"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="?attr/colorPrimary"
        android:contentDescription="Words"
        android:minWidth="56sp"
        app:layout_constraintTop_toTopOf="parent">


        <ImageButton
            android:id="@+id/imageButton"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_alignParentRight="false"
            android:layout_gravity="left"
            android:background="#3F51B5"
            android:maxWidth="10dp"
            android:onClick="onBackClick"
            android:scaleType="fitEnd"
            android:src="@drawable/arrow_with_logo"
            tools:layout_editor_absoluteX="379dp"
            tools:layout_editor_absoluteY="12dp" />

        <TextView
            android:id="@+id/title"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="Inspiration Leaderboard"
            android:textColor="#FFFFFF"
            android:textSize="20sp"
            tools:layout_editor_absoluteX="69dp"
            tools:layout_editor_absoluteY="18dp" />

    </android.support.v7.widget.Toolbar>

    <android.support.v7.widget.RecyclerView
        android:id="@+id/people"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/toolbar"
        tools:layout_editor_absoluteX="3dp" />

</android.support.constraint.ConstraintLayout>