(refs #37)Add participants to issue detail

The design is inherited from Github.

src/main/scala/app/IssuesController.scala

@@ -62,9 +62,12 @@ trait IssuesControllerBase extends ControllerBase {
     val issueId = params("id")
 
     getIssue(owner, name, issueId) map {
+      val comments = getComments(owner, name, issueId.toInt)
+      val participantSet = comments.foldRight(Set(owner)) { (comment, set) => set + comment.commentedUserName }
       issues.html.issue(
           _,
-          getComments(owner, name, issueId.toInt),
+          comments,
+          participantSet,
           getIssueLabels(owner, name, issueId.toInt),
           (getCollaborators(owner, name) :+ owner).sorted,
           getMilestones(owner, name),

src/main/twirl/issues/issue.scala.html

@@ -1,5 +1,6 @@
 @(issue: model.Issue,
   comments: List[model.IssueComment],
+  participants: Set[String],
   issueLabels: List[model.Label],
   collaborators: List[String],
   milestones: List[model.Milestone],
@@ -81,6 +82,10 @@
           </div>
         </div>
       </div>
+      <div class="issue-participants">
+        @participants.size participants
+        @participants.map { participant => @avatar(participant, 20) }
+      </div>
       @comments.map { comment =>
         @if(comment.action != "close" && comment.action != "reopen"){
         <div class="issue-avatar-image">@avatar(comment.commentedUserName, 48)</div>

src/main/webapp/assets/common/css/gitbucket.css

@@ -540,6 +540,11 @@ div.issue-avatar-image {
 }
 
 div.issue-box {
+  margin-bottom: 5px;
+  margin-left: 50px;
+}
+
+div.issue-participants {
   margin-bottom: 15px;
   margin-left: 50px;
 }