add jinja example

examples/jinja_example.py

@@ -0,0 +1,18 @@
+## To use this example:
+# curl -d '{"name": "John Doe"}' localhost:8000
+
+from sanic import Sanic
+from sanic.response import html
+from jinja2 import Template
+
+template = Template('Hello {{ name }}!')
+
+app = Sanic(__name__)
+
+@app.route('/')
+async def test(request):
+    data = request.json
+    return html(template.render(**data))
+
+
+app.run(host="0.0.0.0", port=8000)