Enable subclasses overriding namespace root key

README.md

@@ -107,6 +107,44 @@ Then render it from Erb.
 
 Much better!
 
+### Namespacing forms
+
+By default Superform will namespace a form based on the ActiveModel model name param key.
+
+```ruby
+class UserForm < Superform::Rails::Form
+  def template
+    render field(:email).input
+  end
+end
+
+render LoginForm.new(User.new)
+# This will render inputs with the name `user[email]`
+
+render LoginForm.new(Admin::User.new)
+# This will render inputs with the name `admin_user[email]`
+```
+
+If you want to customize the form namespace, you can override the `key` method in your form.
+
+```ruby
+class UserForm < Superform::Rails::Form
+  def template
+    render field(:email).input
+  end
+
+  def key
+    "user"
+  end
+end
+
+render UserForm.new(User.new)
+# This will render inputs with the name `user[email]`
+
+render UserForm.new(Admin::User.new)
+# This will also render inputs with the name `user[email]`
+````
+
 ## Form field guide
 
 Superform tries to strike a balance between "being as close to HTML forms as possible" and not requiring a lot of boilerplate to create forms. This example is contrived, but it shows all the different ways you can render a form.
@@ -165,6 +203,7 @@ class SignupForm < ApplicationForm
 end
 ```
 
+
 ## Extending Superforms
 
 The best part? If you have forms with a completely different look and feel, you can extend the forms just like you would a Ruby class:

lib/superform/rails.rb

@@ -20,7 +20,6 @@ class Form < Component
           :field,
           :collection,
           :namespace,
-          :key,
           :assign,
           :serialize,
         to: :@namespace
@@ -80,7 +79,7 @@ def initialize(model, action: nil, method: nil, **attributes)
         @action = action
         @method = method
         @attributes = attributes
-        @namespace = Namespace.root(model.model_name.param_key, object: model, field_class: self.class::Field)
+        @namespace = Namespace.root(key, object: model, field_class: self.class::Field)
       end
 
       def around_template(&)
@@ -107,6 +106,10 @@ def submit(value = submit_value, **attributes)
         )
       end
 
+      def key
+        @model.model_name.param_key
+      end
+
       protected
         def authenticity_token_field
           input(