新增：issue和里程碑列表接口

app/controllers/api/v1/issues_controller.rb

@@ -0,0 +1,23 @@
+class Api::V1::IssuesController < Api::V1::BaseController 
+
+  before_action :require_public_and_member_above, only: [:index] 
+
+  def index 
+    @object_results = Api::V1::Issues::ListService.call(@project, query_params, current_user)
+    @issues = kaminari_paginate(@object_results)
+  end
+
+  private 
+
+  def query_params
+    params.permit(
+      :category,
+      :participant_category, 
+      :keyword, :author_id, 
+      :milestone_id, :assigner_id,
+      :status_id, 
+      :sort_by, :sort_direction, 
+      :issue_tag_ids => [])
+  end
+
+end