Include type column for labels

app/models/label.rb

@@ -176,6 +176,7 @@ class Label < ActiveRecord::Base
 
   def as_json(options = {})
     super(options).tap do |json|
+      json[:type] = self.type
       json[:priority] = priority(options[:project]) if options.key?(:project)
     end
   end

spec/fixtures/api/schemas/issue.json

@@ -39,6 +39,7 @@
             "type": "string",
             "pattern": "^#[0-9A-Fa-f]{3}{1,2}+$"
           },
+          "type": { "type": "string" },
           "title": { "type": "string" },
           "priority": { "type": ["integer", "null"] }
         },