diff --git a/app/models/concerns/active_fields/customizable_concern.rb b/app/models/concerns/active_fields/customizable_concern.rb
index b06aef6..c95fd91 100644
--- a/app/models/concerns/active_fields/customizable_concern.rb
+++ b/app/models/concerns/active_fields/customizable_concern.rb
@@ -85,12 +85,12 @@ def active_fields
         ActiveFields.config.field_base_class.for(model_name.name)
       end
 
-      def available_field_types
-        ActiveFields.registry.field_types_for(model_name.name) || []
+      def available_field_type_names
+        ActiveFields.registry.field_type_names_for(model_name.name).to_a
       end
 
       def available_field_class_names
-        ActiveFields.config.fields.values_at(*available_field_types)
+        ActiveFields.config.fields.values_at(*available_field_type_names)
       end
     end
 
diff --git a/app/models/concerns/active_fields/field_concern.rb b/app/models/concerns/active_fields/field_concern.rb
index 6d03680..9123512 100644
--- a/app/models/concerns/active_fields/field_concern.rb
+++ b/app/models/concerns/active_fields/field_concern.rb
@@ -90,7 +90,7 @@ def type_name
     end
 
     def available_customizable_types
-      ActiveFields.registry.customizable_types_for(type_name) || []
+      ActiveFields.registry.customizable_types_for(type_name).to_a
     end
 
     private
@@ -111,8 +111,8 @@ def validate_default_value
     end
 
     def validate_customizable_model_allows_type
-      allowed_types = ActiveFields.registry.field_types_for(customizable_type) || []
-      return true if allowed_types.include?(type_name)
+      allowed_type_names = ActiveFields.registry.field_type_names_for(customizable_type).to_a
+      return true if allowed_type_names.include?(type_name)
 
       errors.add(:customizable_type, :inclusion)
       false
diff --git a/lib/active_fields/registry.rb b/lib/active_fields/registry.rb
index 2fe8db5..22d2963 100644
--- a/lib/active_fields/registry.rb
+++ b/lib/active_fields/registry.rb
@@ -10,25 +10,25 @@ def initialize
       @customizables = {}
     end
 
-    def add(field_type, customizable_type)
-      if ActiveFields.config.type_names.exclude?(field_type)
-        raise ArgumentError, "undefined ActiveFields type provided for #{customizable_type}: #{field_type}"
+    def add(field_type_name, customizable_type)
+      if ActiveFields.config.type_names.exclude?(field_type_name)
+        raise ArgumentError, "undefined ActiveFields type provided for #{customizable_type}: #{field_type_name}"
       end
 
-      @fields[field_type] ||= Set.new
-      @fields[field_type] << customizable_type
+      @fields[field_type_name] ||= Set.new
+      @fields[field_type_name] << customizable_type
 
       @customizables[customizable_type] ||= Set.new
-      @customizables[customizable_type] << field_type
+      @customizables[customizable_type] << field_type_name
 
       nil
     end
 
-    def customizable_types_for(field_type)
-      @fields[field_type]
+    def customizable_types_for(field_type_name)
+      @fields[field_type_name]
     end
 
-    def field_types_for(customizable_type)
+    def field_type_names_for(customizable_type)
       @customizables[customizable_type]
     end
   end
diff --git a/spec/dummy/config/environments/development.rb b/spec/dummy/config/environments/development.rb
index a26e182..1d4bbc2 100644
--- a/spec/dummy/config/environments/development.rb
+++ b/spec/dummy/config/environments/development.rb
@@ -11,7 +11,7 @@
   config.enable_reloading = true
 
   # Do not eager load code on boot.
-  config.eager_load = true
+  config.eager_load = false
 
   # Show full error reports.
   config.consider_all_requests_local = true