Add ipfs package

packages/ipfs.rb

+require 'package'
+
+class Ipfs < Package
+  description 'A peer-to-peer hypermedia protocol'
+  homepage 'https://ipfs.io'
+  version '0.4.13'
+  source_url 'https://github.com/ipfs/go-ipfs/archive/v0.4.13.tar.gz'
+  source_sha256 '9d5f2ef17a8bd4040fb4246c694034ec0ff323bc07d3f1469ce0877892695f31'
+
+  depends_on 'go' => :build
+  depends_on 'fuse'
+
+  def self.build
+    system 'mkdir -p ../src/github.com/ipfs/go-ipfs'
+    system 'cp -aT . ../src/github.com/ipfs/go-ipfs/'
+    system 'mv ../src .'
+    system 'export GOPATH=`pwd`; cd src/github.com/ipfs/go-ipfs; make build'
+  end
+
+  def self.install
+    Dir.chdir 'src/github.com/ipfs/go-ipfs' do
+      system "install -D -d -m 00755 #{CREW_DEST_DIR}/usr/local/bin"
+      system "install -D -m 00755 cmd/ipfs/ipfs #{CREW_DEST_DIR}/usr/local/bin/ipfs"
+    end
+  end
+end