npm docs

[ghost]

It would not be fair if I publish the package on npm with my username, but if someone is willing to do it:
https://docs.npmjs.com/cli/publish
this process will grant the npm install rapidjson [@Version] capability.

[coveralls]

Coverage remained the same at 100.0% when pulling f9810e5 on milkandsour:master into 2a3fbda on miloyip:master.