Render category descriptions differently on the categories page

app/serializers/category_detailed_serializer.rb

@@ -10,6 +10,7 @@ class CategoryDetailedSerializer < ApplicationSerializer
              :topics_month,
              :topics_year,
              :description,
+             :description_excerpt,
              :is_uncategorized
 
   has_many :featured_users, serializer: BasicUserSerializer
@@ -39,4 +40,8 @@ class CategoryDetailedSerializer < ApplicationSerializer
     return displayable_topics.present?
   end
 
+  def description_excerpt
+    PrettyText.excerpt(description,300) if description
+  end
+
 end