web3.js文档：
网址是敏感词，算了，不贴了
Introducing Web3 Plugins
https://medium.com/metamask/introducing-the-next-evolution-of-the-web3-wallet-4abdf801a4ee
MetaMask Plugin System Developer Alpha Introduction
https://www.youtube.com/watch?v=VkvElJY6uLs&feature=youtu.be