Allow set group avatar when create group. Not only edit page

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

app/views/groups/new.html.haml

@@ -13,6 +13,17 @@
     .col-sm-10
       = f.text_area :description, maxlength: 250, class: "form-control js-gfm-input", rows: 4
 
+  .form-group.group-description-holder
+    = f.label :avatar, "Group avatar", class: 'control-label'
+    .col-sm-10
+      %a.choose-btn.btn.btn-small.js-choose-group-avatar-button
+        %i.icon-paper-clip
+        %span Choose File ...
+       
+      %span.file_name.js-avatar-filename File name...
+      = f.file_field :avatar, class: "js-group-avatar-input hidden"
+      .light The maximum file size allowed is 100KB.
+
   .form-group
     .col-sm-2
     .col-sm-10