tweak request timeout settings for heroku

* use Rack::Timeout, set to 20s
* set unicorn timeout to 25s

Ideally these are set lower, around 10s/15s, however we need to reduce long-running requests (such as notifier batch pulls) before we can safely do this.

Gemfile

@@ -54,3 +54,4 @@ end
 gem 'newrelic_rpm'
 gem 'newrelic_moped'
 gem 'unicorn'
+gem "rack-timeout"

Gemfile.lock

@@ -117,6 +117,7 @@ GEM
       rack
     rack-test (0.6.1)
       rack (>= 1.0)
+    rack-timeout (0.0.4)
     raindrops (0.10.0)
     rake (0.9.2.2)
     rdiscount (1.6.8)
@@ -190,6 +191,7 @@ DEPENDENCIES
   pry
   pry-nav
   rack-test
+  rack-timeout
   rake
   rdiscount
   rest-client

config.ru

+require "rack-timeout"
+use Rack::Timeout           # Call as early as possible so rack-timeout runs before other middleware.
+Rack::Timeout.timeout = 20
+
 require './app'
 run Sinatra::Application
 

config/unicorn.rb

 worker_processes 4
-timeout 30
+timeout 25
 preload_app true