Summary: Add a placeholder for datepicker fields

 - Legacy-Id: 8916

Author: OleLaursen

ietf/utils/fields.py

@@ -60,5 +60,7 @@ def __init__(self, date_format, picker_settings={}, *args, **kwargs):
 
         self.widget.attrs["data-provide"] = "datepicker"
         self.widget.attrs["data-date-format"] = date_format
+        if "placeholder" not in self.widget.attrs:
+            self.widget.attrs["placeholder"] = date_format
         for k, v in picker_settings.iteritems():
             self.widget.attrs["data-date-%s" % k] = v