Updated group timelines and sorting

• Updated:
- group timelines and sorting

app/models/group_categories.rb

@@ -2,10 +2,10 @@
 #
 # 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
+#  id         :bigint(8)        not null, primary key
+#  created_at :datetime         not null
+#  updated_at :datetime         not null
+#  text       :string           default(""), not null
 #
 
 class GroupCategories < ApplicationRecord