remove heroku example

examples/heroku/Procfile

@@ -1 +0,0 @@
-web: python server.py

examples/heroku/requirements.txt

@@ -1,27 +0,0 @@
--i https://pypi.org/simple
-aiofiles==0.4.0
-aniso8601==3.0.2
-certifi==2018.8.24
-chardet==3.0.4
-click==7.0
-graphene==2.1.3
-graphql-core==2.1
-graphql-relay==0.4.5
-graphql-server-core==1.1.1
-h11==0.8.1
-idna==2.7
-jinja2==2.10
-markupsafe==1.0
-parse==1.9.0
-promise==2.2.1
-python-multipart==0.0.5
-pyyaml==3.13
-requests==2.19.1
-responder==0.0.3
-rfc3986==1.1.0
-rx==1.6.1
-six==1.11.0
-starlette==0.4.1
-urllib3==1.23
-uvicorn==0.3.12
-websockets==6.0

examples/heroku/server.py

@@ -1,12 +0,0 @@
-import os
-import responder
-
-api = responder.API(enable_hsts=True)
-
-
-@api.route("/")
-def route(req, resp):
-    resp.text = "hello, world!"
-
-
-api.run(port=int(os.environ["PORT"]))