FIX: Avoid using GlobalSetting for crowd_custom_html (#20)

The discourse.conf file doesn't handle strings with single quotes in them. Therefore we can't use the GlobalSetting interface, and need to reach directly for the ENV.

Not ideal, and can possibly be improved in future updates of 'launcher', and the discourse.conf file. For now, this commit will solve the issue for this plugin.

plugin.rb

@@ -127,7 +127,12 @@ def set_groups(user, auth)
   end
 end
 
-class CrowdAuthenticator < ::Auth::OAuth2Authenticator
+class ::Auth::CrowdAuthenticator < ::Auth::OAuth2Authenticator
+  # The discourse.conf file doesn't handle strings with single quotes in them.
+  # Therefore we can't use the GlobalSetting interface, and need to reach directly for the ENV.
+  # Not ideal, and can possibly be improved in future updates of 'launcher', and the discourse.conf file.
+  CROWD_HTML = ENV["DISCOURSE_CROWD_CUSTOM_HTML"]
+
   def register_middleware(omniauth)
     return unless GlobalSetting.try(:crowd_server_url).present?
 
@@ -155,8 +160,8 @@ def get_credentials
           html "\n<input type='hidden' name='authenticity_token' value='#{token}'/>" if token
           button 'Login'
 
-          if GlobalSetting.respond_to?(:crowd_custom_html)
-            html GlobalSetting.crowd_custom_html
+          if ::Auth::CrowdAuthenticator::CROWD_HTML
+            html ::Auth::CrowdAuthenticator::CROWD_HTML
           end
         end.to_response
       end
@@ -195,4 +200,4 @@ def enabled?
 end
 
 auth_provider title: GlobalSetting.try(:crowd_title),
-              authenticator: CrowdAuthenticator.new('crowd')
+              authenticator: ::Auth::CrowdAuthenticator.new('crowd')