```ruby
module Entity
  class Category < Base
    expose :id#, documentation: {type: 'Integer', desc: 'Category ID'}
    expose :name#, documentation: {type: 'String', desc: 'The name of the category of articles'}
    expose :icon#, documentation: {type: 'String', desc: 'An icon that represents the category'}
    expose :keywords#, documentation: {type: 'String', desc: 'Keywords that will be used for internal search and SEO'}
    expose :title_tag#, documentation: {type: 'String', desc: 'An alternate title tag that will be used if provided'}
    expose :meta_description#, documentation: {type: 'String', desc: 'A short description for SEO and internal purposes'}
    expose :rank#, documentation: {type: 'String', desc: 'The rank can be used to determine the ordering of categories'}
    expose :front_page#, documentation: {type: 'String', desc: 'Whether or not the category should appear on the front page'}
    expose :active#, documentation: {type: 'String', desc: 'Whether or not the category is live on the site'}
    expose :created_at
    expose :updated_at
    expose :docs, using: Entity::Doc, if: { docs: true }
  end
end
```

Add slug to categories entity
user
```ruby
module Entity
  class Category < Base
    expose :id#, documentation: {type: 'Integer', desc: 'Category ID'}
    expose :slug do |category, options| 
      category.to_param
    end#, documentation: {type: 'String', desc: 'Parameterised Category ID'}
    expose :name#, documentation: {type: 'String', desc: 'The name of the category of articles'}
    expose :icon#, documentation: {type: 'String', desc: 'An icon that represents the category'}
    expose :keywords#, documentation: {type: 'String', desc: 'Keywords that will be used for internal search and SEO'}
    expose :title_tag#, documentation: {type: 'String', desc: 'An alternate title tag that will be used if provided'}
    expose :meta_description#, documentation: {type: 'String', desc: 'A short description for SEO and internal purposes'}
    expose :rank#, documentation: {type: 'String', desc: 'The rank can be used to determine the ordering of categories'}
    expose :front_page#, documentation: {type: 'String', desc: 'Whether or not the category should appear on the front page'}
    expose :active#, documentation: {type: 'String', desc: 'Whether or not the category is live on the site'}
    expose :created_at
    expose :updated_at
    expose :docs, using: Entity::Doc, if: { docs: true }
  end
end
```
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