Add "Network" to the global navigation.

src/main/twirl/header.scala.html

@@ -34,6 +34,9 @@
     <th class="box-header@if(active=="wiki"){ active}">
       <a href="@url(repository)/wiki">Wiki</a>
     </th>
+    <th class="box-header@if(active=="network"){ active}">
+      <a href="@url(repository)/network/members">Network</a>
+    </th>
     @if(loginAccount.isDefined && (loginAccount.get.isAdmin || loginAccount.get.userName == repository.owner)){
     <th class="box-header@if(active=="settings"){ active}">
       <a href="@url(repository)/settings">Settings</a>

src/main/twirl/repo/forked.scala.html

@@ -3,6 +3,7 @@
 @import context._
 @import view.helpers._
 @html.main(s"${repository.owner}/${repository.name}", Some(repository)) {
+  @html.header("network", repository)
   <ul class="nav nav-tabs">
     <li class="active"><a href="@url(repository)/network/members">Members</a></li>
   </ul>

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

@@ -62,7 +62,7 @@ table.global-nav {
 table.global-nav th {
   padding-top: 5px;
   padding-bottom: 8px;
-  width: 20%;
+  width: 16%;
   border-bottom: 2px solid silver;
   cursor: pointer;
 }