add go modules versioning and update README for it

Author: daluu

README.md

@@ -6,9 +6,10 @@ This is a proof of concept prototype. Not fully working at the moment. See the s
 
 ## Setup
 
-1. Have a version of [go](https://golang.org/dl/) installed. Recommend go 1.5+. And set up your $GOPATH and $GOBIN environment variables.
-2. Get a copy of gorrs for go: ```go get github.com/daluu/gorrs```
-3. Get gorrs external dependencies: ```go get github.com/gorilla/rpc``` and ```go get github.com/divan/gorilla-xmlrpc/xml```. Sorry there are several go package managers, and not a true single standard yet. So I don't want to stick with any at the moment.
+1. Have a version of [go](https://golang.org/dl/) installed. Recommend go 1.13+. And set up your $GOPATH and $GOBIN environment variables.
+2. Get a copy of gorrs: ```go get -u github.com/daluu/gorrs```
+
+The combination of go modules (`go.mod` + `go.sum`) & `go get -u` should pick up all the (versioned) dependencies to build gorrs. If you prefer using a different method of go dependency management, feel free to do so yourself.
 
 ## Intended usage (when gorrs is fully working):
 

go.mod

@@ -0,0 +1,9 @@
+module github.com/daluu/gorrs
+
+go 1.13
+
+require (
+	github.com/divan/gorilla-xmlrpc v0.0.0-20190926132722-f0686da74fda
+	github.com/gorilla/rpc v1.2.0
+	github.com/rogpeppe/go-charset v0.0.0-20190617161244-0dc95cdf6f31 // indirect
+)

go.sum

@@ -0,0 +1,6 @@
+github.com/divan/gorilla-xmlrpc v0.0.0-20190926132722-f0686da74fda h1:q6BJCx6rxRJv/sLreclgzu4dK4dPF8x48afqcXtRtLQ=
+github.com/divan/gorilla-xmlrpc v0.0.0-20190926132722-f0686da74fda/go.mod h1:3Cp6mWQcmK3erqkPrriKEkSpok0LO1uB2M5GxGzifhc=
+github.com/gorilla/rpc v1.2.0 h1:WvvdC2lNeT1SP32zrIce5l0ECBfbAlmrmSBsuc57wfk=
+github.com/gorilla/rpc v1.2.0/go.mod h1:V4h9r+4sF5HnzqbwIez0fKSpANP0zlYd3qR7p36jkTQ=
+github.com/rogpeppe/go-charset v0.0.0-20190617161244-0dc95cdf6f31 h1:DE4LcMKyqAVa6a0CGmVxANbnVb7stzMmPkQiieyNmfQ=
+github.com/rogpeppe/go-charset v0.0.0-20190617161244-0dc95cdf6f31/go.mod h1:qgYeAmZ5ZIpBWTGllZSQnw97Dj+woV0toclVaRGI8pc=