added error handling

app/templates/error.html

@@ -0,0 +1,15 @@
+{% extends "base.html" %}
+{% block content %}
+
+<style>
+.container {
+    text-align: center;
+}
+</style>
+
+<div class="container">
+  <h1>> Error:</h1>
+  <h1 style="color:#ffffff;">{{ error_message }}</h1>
+</div>
+
+{% endblock %}