docs(2/pin)

ipfs1 docs read:

```
btc λ. ipfs pin
ipfs pin -

Commands:

        add         pin an ipfs object to local storage.
        rm          unpin an ipfs object from local storage.

        Use "pin help <command>" for more information about a command.
```

License: MIT
Signed-off-by: Brian Tiger Chow <brian@perfmode.com>