add purchase template

src/templates/purchase.html

@@ -0,0 +1,15 @@
+{% extends 'base.html' %}
+
+{% block content %}
+    {% if current_user.is_authenticated %}
+        <div class="jumbotron">
+            <h1 class="display-3">File Upload</h1>
+            <br>
+            <form method="POST" action="">
+                <p><input type="submit" value="buy" class="btn btn-primary"></p>
+            </form>
+        </div>
+    {% else %}
+        <p><a href="{{ url_for_security('login') }}">Log in</a> to upload an animation.</p>
+    {% endif %}
+{% endblock %}