Add simple landing page to viewer

viewers/main/viewer/main.py

@@ -15,7 +15,7 @@ indexer_url = os.environ.get('INDEXER_URL', 'http://indexer')
 
 @app.route('/')
 def check():
-    return 'OK'
+    return flask.render_template('home.html')
 
 
 @app.route('/shipping')

viewers/main/viewer/templates/home.html

@@ -0,0 +1,17 @@
+{% extends "base.html" %}
+{% block title %}Home{% endblock %}
+
+{% block navbar_nav %}
+<li class="nav-item">
+    <a class="nav-link" href="/shipping">Shipping</a>
+</li>
+{% endblock %}
+
+{% block container %}
+<div class="row mt-3">
+    <div class="col">
+        <h2>Email Assistant</h2>
+        <p>Let's get trackin!</p>
+    </div>
+</div>
+{% endblock %}