filecoin 0.4.0

Filecoin (https://filecoin.io/) is a distributed storage network based on a blockchain mechanism. Filecoin miners provide storage capacity for the network, earning FIL by periodically prooving the specified capacity is provided to the network. The Filecoin blockchain maintains the ledger for FIL transactions, and implements the Filecoin VM for the execution of contracts and market mechanisms. These include storage deals, where clients pay miners to store data in the network. This gem makes use of the JSON RPC API made available by Lotus (https://lotu.sh/), the official implementation of the network.