all: add go.mod

Commands run:
	go mod init
	go mod edit -go=1.11
	go mod tidy
	go list -m all
	go test ./...

Updates golang/go#30228

Change-Id: I78d903d7151790b37f32a06f37427a50fcd2a83b
Reviewed-on: https://go-review.googlesource.com/c/blog/+/167157
Run-TryBot: Bryan C. Mills <bcmills@google.com>
TryBot-Result: Gobot Gobot <gobot@golang.org>
Reviewed-by: Brad Fitzpatrick <bradfitz@golang.org>

go.mod

@@ -0,0 +1,11 @@
+module golang.org/x/blog
+
+go 1.11
+
+require (
+	github.com/gorilla/context v1.1.1
+	golang.org/x/net v0.0.0-20190311183353-d8887717615a
+	golang.org/x/text v0.3.0
+	golang.org/x/tools v0.0.0-20190312151545-0bb0c0a6e846
+	gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637
+)

go.sum

@@ -0,0 +1,12 @@
+github.com/gorilla/context v1.1.1 h1:AWwleXJkX/nhcU9bZSnZoi3h/qGYqQAGhq6zZe/aQW8=
+github.com/gorilla/context v1.1.1/go.mod h1:kBGZzfjB9CEq2AlWe17Uuf7NDRt0dE0s8S51q0aT7Yg=
+golang.org/x/crypto v0.0.0-20190308221718-c2843e01d9a2/go.mod h1:djNgcEr1/C05ACkg1iLfiJU5Ep61QUkGW8qpdssI0+w=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a h1:oWX7TPOiFAMXLq8o0ikBYfCJVlRHBcsciT5bXOrH628=
+golang.org/x/net v0.0.0-20190311183353-d8887717615a/go.mod h1:t9HGtf8HONx5eT2rtn7q6eTqICYqUVnKs3thJo3Qplg=
+golang.org/x/sys v0.0.0-20190215142949-d0b11bdaac8a/go.mod h1:STP8DvDyc/dI5b8T5hshtkjS+E42TnysNCUPdjciGhY=
+golang.org/x/text v0.3.0 h1:g61tztE5qeGQ89tm6NTjjM9VPIm088od1l6aSorWRWg=
+golang.org/x/text v0.3.0/go.mod h1:NqM8EUOU14njkJ3fqMW+pc6Ldnwhi/IjpwHt7yyuwOQ=
+golang.org/x/tools v0.0.0-20190312151545-0bb0c0a6e846 h1:0oJP+9s5Z3MT6dym56c4f7nVeujVpL1QyD2Vp/bTql0=
+golang.org/x/tools v0.0.0-20190312151545-0bb0c0a6e846/go.mod h1:LCzVGOaR6xXOjkQ3onu1FJEFr0SW1gC7cKk1uF8kGRs=
+gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637 h1:yiW+nvdHb9LVqSHQBXfZCieqV4fzYhNBql77zY0ykqs=
+gopkg.in/tomb.v2 v2.0.0-20161208151619-d5d1b5820637/go.mod h1:BHsqpu/nsuzkT5BpiH1EMZPLyqSMM8JbIavyFACoFNk=