support npm tag

[dead-horse]

npm tag [email protected] latest

[dead-horse]

request opts

{ url: 
   { protocol: 'https:',
     slashes: true,
     auth: 'user:pass',
     host: 'registry.npmjs.org',
     port: null,
     hostname: 'registry.npmjs.org',
     hash: null,
     search: null,
     query: null,
     pathname: '/moduletest/latest',
     path: '/moduletest/latest',
     href: 'https://registry.npmjs.org/moduletest/latest' },
  method: 'PUT',
  ca: null,
  localAddress: undefined,
  cert: null,
  key: null,
  strictSSL: true,
  headers: 
   { accept: 'application/json',
     'user-agent': 'node/v0.11.12 darwin x64',
     'content-type': 'application/json',
     'content-length': 7 },
  proxy: null,
  body: '"0.0.5"' }

[fengmk2]

how to use this command in ali npm?