Show only people who have assigned issues in assignee dropdown

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

app/controllers/projects/issues_controller.rb

@@ -29,6 +29,7 @@ class Projects::IssuesController < Projects::ApplicationController
     sort_param = params[:sort] || 'newest'
     @sort = sort_param.humanize unless sort_param.empty?
 
+    @assignees = User.where(id: @project.issues.pluck(:assignee_id))
 
     respond_to do |format|
       format.html

app/views/projects/issues/_issues.html.haml

@@ -49,7 +49,7 @@
                 Any
               = link_to project_filter_path(assignee_id: 0) do
                 Unassigned
-            - @project.team.members.sort_by(&:name).each do |user|
+            - @assignees.sort_by(&:name).each do |user|
               %li
                 = link_to project_filter_path(assignee_id: user.id) do
                   = image_tag avatar_icon(user.email), class: "avatar s16", alt: ''