allow queue worker process to hot reload if entr is available

Procfile

@@ -1,3 +1,3 @@
 assets: yarn watch
 web: PORT=8000 python app.py
-queue: flask rq worker
+queue: ./script/dev_queue

README.md

@@ -39,6 +39,10 @@ locally:
   running on the default port of 6379. You can ensure that Redis is running by
   executing `redis-cli` with no options and ensuring a connection is succesfully made.
 
+* [`entr`](http://www.entrproject.org/)
+  This dependency is optional. If present, the queue worker process will hot
+  reload in development.
+
 ### Cloning
 This project contains git submodules. Here is an example clone command that will
 automatically initialize and update those modules:

script/dev_queue

@@ -0,0 +1,11 @@
+#!/bin/bash
+
+# script/dev_queue: Run the queue with entr if available
+
+set -e
+
+if [[ `command -v entr` ]]; then
+  find atst | entr -r flask rq worker
+else
+  flask rq worker
+fi