Added option to remove issue assignee on project issue page and issue edit page

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

Conflicts:
	CHANGELOG

CHANGELOG

+v 6.6.5
+  - Added option to remove issue assignee on project issue page and issue edit page (Jason Blanchard)
+
 v 6.6.4
   - Add missing html escape for highlighted code blocks in comments, issues
 

app/assets/javascripts/project_users_select.js.coffee

@@ -10,6 +10,16 @@
         query: (query) ->
           Api.projectUsers project_id, query.term, (users) ->
             data = { results: users }
+
+            nullUser = {
+              name: 'Unassigned',
+              avatar: null,
+              username: 'none',
+              id: ''
+            }
+
+            data.results.unshift(nullUser)
+
             query.callback(data)
 
         initSelection: (element, callback) ->
@@ -35,8 +45,13 @@
     else
       avatar = gon.relative_url_root + "/assets/no_avatar.png"
 
+    if user.id == ''
+      avatarMarkup = ''
+    else
+      avatarMarkup = "<div class='user-image'><img class='avatar s24' src='#{avatar}'></div>"
+
     "<div class='user-result'>
-       <div class='user-image'><img class='avatar s24' src='#{avatar}'></div>
+       #{avatarMarkup}
        <div class='user-name'>#{user.name}</div>
        <div class='user-username'>#{user.username}</div>
      </div>"

spec/features/issues_spec.rb

@@ -43,6 +43,31 @@ describe "Issues" do
         page.should have_content project.name
       end
     end
+
+  end
+
+  describe "Editing issue assignee" do
+    let!(:issue) do
+      create(:issue,
+             author: @user,
+             assignee: @user,
+             project: project)
+    end
+
+    it 'allows user to select unasigned', :js => true do
+      visit edit_project_issue_path(project, issue)
+
+      page.should have_content "Assign to #{@user.name}"
+
+      page.first('#s2id_issue_assignee_id').click
+      sleep 2 # wait for ajax stuff to complete
+      page.first('.user-result').click
+
+      click_button "Save changes"
+
+      page.should have_content "Assignee: Select assignee"
+      issue.reload.assignee.should be_nil
+    end
   end
 
   describe "Filter issue" do
@@ -245,6 +270,28 @@ describe "Issues" do
         page.should have_content milestone.title
       end
     end
+
+    describe 'removing assignee' do
+      let(:user2) { create(:user) }
+
+      before :each do
+        issue.assignee = user2
+        issue.save
+      end
+
+      it 'allows user to remove assignee', :js => true do
+        visit project_issue_path(project, issue)
+        page.should have_content "Assignee: #{user2.name}"
+
+        page.first('#s2id_issue_assignee_id').click
+        sleep 2 # wait for ajax stuff to complete
+        page.first('.user-result').click
+
+        page.should have_content "Assignee: Unassigned"
+        sleep 2 # wait for ajax stuff to complete
+        issue.reload.assignee.should be_nil
+      end
+    end
   end
 
   def first_issue