Add placeholders from and to

app/views/projects/compare/_form.html.haml

@@ -15,9 +15,9 @@
       .pull-left
         - if params[:to] && params[:from]
           = link_to 'switch', {from: params[:to], to: params[:from]}, {class: 'commits-compare-switch has_tooltip', title: 'Switch base of comparison'}
-        = text_field_tag :from, params[:from], class: "input-xlarge input-xpadding"
+        = text_field_tag :from, params[:from], placeholder: "from", class: "input-xlarge input-xpadding"
         = "..."
-        = text_field_tag :to, params[:to], class: "input-xlarge input-xpadding"
+        = text_field_tag :to, params[:to], placeholder: "to", class: "input-xlarge input-xpadding"
       .pull-left
          
         = submit_tag "Compare", class: "btn btn-create commits-compare-btn"