making 'simple_form' the default form class but allowing to change

lib/generators/simple_form/templates/simple_form.rb

@@ -55,6 +55,9 @@ SimpleForm.setup do |config|
   # You can define the class to use on all labels. Default is nil.
   # config.label_class = nil
 
+  # You can define the class to use on all forms. Default is simple_form.
+  # config.form_class = :simple_form
+
   # Whether attributes are required by default (or not). Default is true.
   # config.required_by_default = true
 

lib/simple_form.rb

@@ -83,6 +83,10 @@ module SimpleForm
   mattr_accessor :label_class
   @@label_class = nil
 
+  # You can define the class to use on all forms. Default is simple_form.
+  mattr_accessor :form_class
+  @@form_class = :simple_form
+
   # Whether attributes are required by default (or not).
   mattr_accessor :required_by_default
   @@required_by_default = true

lib/simple_form/action_view_extensions/form_helper.rb

@@ -40,7 +40,7 @@ module SimpleForm
               else dom_class(record_or_name_or_array)
             end
             options[:html] ||= {}
-            options[:html][:class] = "simple_form \#{css_class} \#{options[:html][:class]}".strip
+            options[:html][:class] = "\#{SimpleForm.form_class} \#{css_class} \#{options[:html][:class]}".strip
 
             with_custom_field_error_proc do
               #{helper}(record_or_name_or_array, *(args << options), &block)