fix attach_cmd where meta would not be updated

pubs/commands/attach_cmd.py

@@ -38,6 +38,7 @@ def command(args):
         else:
             pass # TODO warn if file does not exists
         paper.docpath = document
+        rp.push_paper(paper, overwrite=True, event=False)
     except ValueError, v:
         ui.error(v.message)
         ui.exit(1)