DEV: Do not require restart to enable signatures

add_to_serializer checks whether the plugin is enabled at runtime, and supports multisite environments

plugin.rb

@@ -20,24 +20,22 @@ after_initialize do
 
   register_editable_user_custom_field [:see_signatures, :signature_url, :signature_raw]
 
-  if SiteSetting.signatures_enabled then
-    add_to_serializer(:post, :user_signature, false) {
-      if SiteSetting.signatures_advanced_mode then
-        object.user.custom_fields['signature_cooked'] if object.user
-      else
-        object.user.custom_fields['signature_url'] if object.user
-      end
-    }
+  add_to_serializer(:post, :user_signature) {
+    if SiteSetting.signatures_advanced_mode then
+      object.user.custom_fields['signature_cooked'] if object.user
+    else
+      object.user.custom_fields['signature_url'] if object.user
+    end
+  }
 
-    # I guess this should be the default @ discourse. PR maybe?
-    add_to_serializer(:user, :custom_fields, false) {
-      if object.custom_fields == nil then
-        {}
-      else
-        object.custom_fields
-      end
-    }
-  end
+  # I guess this should be the default @ discourse. PR maybe?
+  add_to_serializer(:user, :custom_fields) {
+    if object.custom_fields == nil then
+      {}
+    else
+      object.custom_fields
+    end
+  }
 
   # This is the code responsible for cooking a new advanced mode sig on user update
   DiscourseEvent.on(:user_updated) do |user|