remove flask-script

flask-script has been deprecated by the internal flask.cli module, but
making this carries a few changes with it

* you should add FLASK_APP=application.py and FLASK_DEBUG=1 to your
  environment.sh.
* instead of using `python app.py runserver`, now you must run
  `flask run -p 6012`. The -p command is important - the port must be
  set before the config is loaded, so that it can live reload nicely.
  (https://github.com/pallets/flask/issues/2113#issuecomment-268014481)
* find available commands by just running `flask`.
* run them using flask. eg `flask list_routes`
* define new tasks by giving them the decorator
  `@app.cli.command('task-name')`. Task name isn't needed if it's just
  the same as the function name. Alternatively, if app isn't available
  in the current scope, you can invoke the decorator directly, as seen
  in app/commands.py

app/__init__.py

@@ -7,7 +7,6 @@ import itertools
 import ago
 from itsdangerous import BadSignature
 from flask import (
-    Flask,
     session,
     render_template,
     make_response,
@@ -37,6 +36,7 @@ from werkzeug.exceptions import abort
 from werkzeug.local import LocalProxy
 
 from app import proxy_fix
+from app.config import configs
 from app.asset_fingerprinter import AssetFingerprinter
 from app.its_dangerous_session import ItsdangerousSessionInterface
 from app.notify_client.service_api_client import ServiceAPIClient
@@ -54,8 +54,8 @@ from app.notify_client.models import AnonymousUser
 from app.notify_client.letter_jobs_client import LetterJobsClient
 from app.notify_client.inbound_number_client import InboundNumberClient
 from app.notify_client.billing_api_client import BillingAPIClient
+from app.commands import setup_commands
 from app.utils import get_cdn_domain
-
 from app.utils import gmt_timezones
 
 login_manager = LoginManager()
@@ -82,10 +82,8 @@ billing_api_client = BillingAPIClient()
 current_service = LocalProxy(partial(_lookup_req_object, 'service'))
 
 
-def create_app():
-    from app.config import configs
-
-    application = Flask(__name__)
+def create_app(application):
+    setup_commands(application)
 
     notify_environment = os.environ['NOTIFY_ENVIRONMENT']
 
@@ -128,40 +126,12 @@ def create_app():
 
     application.session_interface = ItsdangerousSessionInterface()
 
-    application.add_template_filter(format_datetime)
-    application.add_template_filter(format_datetime_24h)
-    application.add_template_filter(format_datetime_normal)
-    application.add_template_filter(format_datetime_short)
-    application.add_template_filter(format_time)
-    application.add_template_filter(valid_phone_number)
-    application.add_template_filter(linkable_name)
-    application.add_template_filter(format_date)
-    application.add_template_filter(format_date_normal)
-    application.add_template_filter(format_date_short)
-    application.add_template_filter(format_datetime_relative)
-    application.add_template_filter(format_delta)
-    application.add_template_filter(format_notification_status)
-    application.add_template_filter(format_notification_status_as_time)
-    application.add_template_filter(format_notification_status_as_field_status)
-    application.add_template_filter(format_notification_status_as_url)
-    application.add_template_filter(formatted_list)
-    application.add_template_filter(nl2br)
-    application.add_template_filter(format_phone_number_human_readable)
-
-    application.after_request(useful_headers_after_request)
-    application.after_request(save_service_after_request)
-    application.before_request(load_service_before_request)
-
-    @application.context_processor
-    def _attach_current_service():
-        return {'current_service': current_service}
+    add_template_filters(application)
 
     register_errorhandlers(application)
 
     setup_event_handlers()
 
-    return application
-
 
 def init_csrf(application):
     csrf.init_app(application)
@@ -185,6 +155,13 @@ def init_csrf(application):
 
 
 def init_app(application):
+    application.after_request(useful_headers_after_request)
+    application.after_request(save_service_after_request)
+    application.before_request(load_service_before_request)
+
+    @application.context_processor
+    def _attach_current_service():
+        return {'current_service': current_service}
 
     @application.before_request
     def record_start_time():
@@ -519,3 +496,25 @@ def setup_event_handlers():
     from app.event_handlers import on_user_logged_in
 
     user_logged_in.connect(on_user_logged_in)
+
+
+def add_template_filters(application):
+    application.add_template_filter(format_datetime)
+    application.add_template_filter(format_datetime_24h)
+    application.add_template_filter(format_datetime_normal)
+    application.add_template_filter(format_datetime_short)
+    application.add_template_filter(format_time)
+    application.add_template_filter(valid_phone_number)
+    application.add_template_filter(linkable_name)
+    application.add_template_filter(format_date)
+    application.add_template_filter(format_date_normal)
+    application.add_template_filter(format_date_short)
+    application.add_template_filter(format_datetime_relative)
+    application.add_template_filter(format_delta)
+    application.add_template_filter(format_notification_status)
+    application.add_template_filter(format_notification_status_as_time)
+    application.add_template_filter(format_notification_status_as_field_status)
+    application.add_template_filter(format_notification_status_as_url)
+    application.add_template_filter(formatted_list)
+    application.add_template_filter(nl2br)
+    application.add_template_filter(format_phone_number_human_readable)