README clarification

Author: Revolucent

README.md

@@ -76,6 +76,8 @@ cdqi Developers
 
 This searches all subdirectories recursively until it finds a managed object model called `Developers.xcdatamodeld`. It then examines the _current version_ of this model and generates proxy classes for each `NSManagedObject`. By default, these proxy classes are placed in the same directory as the managed object model, side by side. `cdqi` has many options to change this behavior if desired, but in most cases the default is what you want. For more options, execute `cdqi --help`.
 
+Note that when working with autogenerated Core Data classes, you should create your proxies with the `--public` flag, otherwise you will get compilation errors.
+
 ### Type Safety
 
 CDQI supports type safety in filter expressions. In the expression `$0.languages.name`, the `name` attribute has been defined as a string in the Core Data model, so it can only be compared to strings. The following will not compile:
@@ -163,3 +165,4 @@ var projectQuery = managedObjectContext.from(Project.self)
 projectQuery = projectQuery.filter(any(project.languages.name == "Swift"))
 projectQuery = projectQuery.order(project.name)
 swiftProjectNames = projectQuery.array(project.name)
+```