Add taskboard button in issues detail

app/coffee/modules/issues/detail.coffee

@@ -150,12 +150,18 @@ class IssueDetailController extends mixOf(taiga.Controller, taiga.PageMixin)
                 }
                 @scope.nextUrl = @navUrls.resolve("project-issues-detail", ctx)
 
+    loadSprint: ->
+        if @scope.issue.milestone
+            return @rs.sprints.get(@scope.issue.project, @scope.issue.milestone).then (sprint) =>
+                @scope.sprint = sprint
+                return sprint
+
     loadInitialData: ->
         project = @.loadProject()
 
         @.fillUsersAndRoles(project.members, project.roles)
 
-        return @.loadIssue()
+        return @.loadIssue().then(=> @.loadSprint())
 
     ###
     # Note: This methods (onUpvote() and onDownvote()) are related to tg-vote-button.

app/locales/taiga/locale-en.json

@@ -1429,6 +1429,8 @@
         "GO_TO_EXTERNAL_REFERENCE": "Go to origin",
         "ACTION_DELETE": "Delete issue",
         "LIGHTBOX_TITLE_BLOKING_ISSUE": "Blocking issue",
+        "LINK_TASKBOARD": "Taskboard",
+        "TITLE_LINK_TASKBOARD": "Go to the taskboard",
         "FIELDS": {
             "PRIORITY": "Priority",
             "SEVERITY": "Severity",

app/partials/issue/issues-detail.jade

@@ -9,6 +9,15 @@ div.wrapper(
     div.main.us-detail
         div.us-detail-header.header-with-actions
             include ../includes/components/mainTitle
+            .action-buttons
+                a.button-gray(
+                    href=""
+                    tg-check-permission="view_milestones"
+                    tg-nav="project-taskboard:project=project.slug,sprint=sprint.slug"
+                    ng-if="sprint && project.is_backlog_activated"
+                    title="{{'ISSUES.TITLE_LINK_TASKBOARD' | translate}}"
+                    translate="ISSUES.LINK_TASKBOARD"
+                )
 
         section.us-story-main-data
             header