Add support for env var DEBSHOTS_ALERT_MESSAGE

If that environment variable is set then it will display on every page.

app/views/layouts/application.html.slim

@@ -14,7 +14,10 @@ html
 
   body
     = render 'layouts/topbar'
+
     #content.grid-container
+      - if Rails.configuration.alert_message
+        .callout.warning.alert-callout-subtle.radius =Rails.configuration.alert_message
       #messages
         = render 'layouts/messages'
       = yield

config/environments/development.rb

@@ -68,6 +68,10 @@ Rails.application.configure do
     }
   ]
 
+  # Show a message on the front page.
+  # TODO: put it into the database and make it configurable online
+  config.alert_message = ENV['DEBSHOTS_ALERT_MESSAGE']
+
   # URL to fetch reviews from the Ubuntu JSON API
   # config.ubuntu_reviews_api_url = 'https://reviews.ubuntu.com/reviews/api/1.0/reviews/filter/en/any/any/any/%s'
 end

config/environments/production.rb

@@ -105,6 +105,10 @@ Rails.application.configure do
     }
   ]
 
+  # Show a message on the front page.
+  # TODO: put it into the database and make it configurable online
+  config.alert_message = ENV['DEBSHOTS_ALERT_MESSAGE']
+
   # URL to fetch reviews from the Ubuntu JSON API
   # config.ubuntu_reviews_api_url = 'https://reviews.ubuntu.com/reviews/api/1.0/reviews/filter/en/any/any/any/%s'