Added group_categories model file, redux

• Added:
- group_categories model file, redux

app/models/group_categories.rb

@@ -0,0 +1,12 @@
+# == Schema Information
+#
+# Table name: group_categories
+#
+#  id          :bigint(8)        not null, primary key
+#  created_at  :datetime         not null
+#  updated_at  :datetime         not null
+#  text        :string           not null
+#
+
+class GroupCategories < ApplicationRecord
+end