Prepare app for working behind a proxy (nginx).

Adapt user form

eveai_app/templates/error/403.html

@@ -0,0 +1,9 @@
+{% extends "base.html" %}
+
+{% block title %}Error 403{% endblock %}
+
+{% block content_title %}Unauthorized Access{% endblock %}
+{% block content_description %}You are not authorized to access this page!{% endblock %}
+{% block content %}
+    <p><a href="{{ url_for('basic_bp.index') }}">Return home</a></p>
+{% endblock %}