set ENV['HEROKU'] explicitly in the heroku:config task

app/models/app_config.rb

@@ -6,7 +6,7 @@ require 'uri'
 class AppConfig < Settingslogic
 
   def self.source_file_name
-    return ENV.to_hash if ENV["STACK"] # Using Heroku
+    return ENV.to_hash if ENV["HEROKU"] # Using Heroku
 
     if Rails.env == 'test' || ENV["CI"] || Rails.env.include?("integration")
       File.join(Rails.root, "config", "application.yml.example")
@@ -18,7 +18,7 @@ class AppConfig < Settingslogic
   namespace Rails.env
 
   def self.load!
-    unless ENV["STACK"]
+    unless ENV["HEROKU"]
       if no_config_file? && !have_old_config_file?
         $stderr.puts <<-HELP
 ******** You haven't set up your Diaspora settings file. **********
@@ -54,7 +54,7 @@ Please do the following:
       Process.exit(1)
     end
 
-    if !ENV["STACK"] && no_cert_file_in_prod?
+    if !ENV["HEROKU"] && no_cert_file_in_prod?
       $stderr.puts <<-HELP
 ******** Diaspora does not know where your SSL-CA-Certificates file is. **********
   Please add the root certificate bundle (this is operating system specific) to application.yml. Defaults:

lib/tasks/heroku.rake

@@ -4,6 +4,7 @@ namespace :heroku do
     CONFIG = YAML.load_file('config/application.yml')['production'] rescue {}
     command = "heroku config:add"
     CONFIG.each {|key, val| command << " #{key}=#{val} " if val }
+    command << " HEROKU=true "
     system command
   end
 end