add python demo example

examples/hello-python/App/web.py

@@ -0,0 +1,33 @@
+import os
+import asyncio
+
+import aioredis
+from aiohttp import web
+
+REDIS_HOST = os.environ.get('REDIS_HOST', 'localhost')
+REDIS_PORT = int(os.environ.get('REDIS_PORT', '6379'))
+REDIS_DB = int(os.environ.get('REDIS_DB', '0'))
+
+redis = aioredis.from_url(f"redis://{REDIS_HOST}:{REDIS_PORT}/{REDIS_DB}")
+app = web.Application()
+routes = web.RouteTableDef()
+
+@routes.get('/')
+async def hello(request):
+    counter = await redis.incr("mycounter")
+    return web.Response(text=f"counter={counter}")
+
+@routes.get('/hello.json')
+async def hello_json(request):
+    counter = await redis.incr("mycounter")
+    data = {'counter': counter}
+    return web.json_response(data)
+
+app.add_routes(routes)
+
+def main():
+    web.run_app(app)
+
+if __name__=='__main__':
+    main()
+