No url found for submodule path 'vendor/github.com/ogier/pflag' in .gitmodules

When I cloned the repo, I got this...

git clone git@github.com:micahhausler/container-tx.git
Cloning into 'container-tx'...
remote: Counting objects: 165, done.
remote: Total 165 (delta 0), reused 0 (delta 0), pack-reused 165
Receiving objects: 100% (165/165), 140.38 KiB | 0 bytes/s, done.
Resolving deltas: 100% (40/40), done.
fatal: No url found for submodule path 'vendor/github.com/ogier/pflag' in .gitmodules

I don't see a .gitmodules so was surprised it even had any way to know that path was supposed to be a submodule.

But I learned from https://stackoverflow.com/a/4185579/47185 that git stores submodule directories with a special mode '160000'. Running git ls-files --stage | grep 160000 confirms that it is a submodule:

160000 45c278ab3607870051a2ea9040bb85fcb8557481 0   vendor/github.com/ogier/pflag
160000 ec7fdbb58eb3e300c8595ad5ac74a5aa50019cc7 0   vendor/github.com/sergi/go-diff
160000 e4d366fc3c7938e2958e662b4258c7a89e1f0e3e 0   vendor/gopkg.in/yaml.v2

I'm guessing you just forgot to add the .gitmodules file to git?

Anyway, the missing submodule leads to this error when I try to build (following the instructions from the Dockerfile):

docker run --rm -v $(pwd):/go/src/github.com/micahhausler/container-tx -w /go/src/github.com/micahhausler/container-tx golang:1.7  go build -v -a -tags netgo -installsuffix netgo -ldflags '-w'
Unable to find image 'golang:1.7' locally
1.7: Pulling from library/golang
ad74af05f5a2: Pull complete 
2b032b8bbe8b: Pull complete 
a9a5b35f6ead: Pull complete 
25d9840c55bc: Pull complete 
abeecada453e: Pull complete 
98b5f0802231: Pull complete 
aca2591b4a7e: Pull complete 
Digest: sha256:93b2b52f1212e97b6650bde1f20f6a359b08c117c57a848970d615fe88623a3d
Status: Downloaded newer image for golang:1.7
main.go:12:2: cannot find package "github.com/ogier/pflag" in any of:
    /go/src/github.com/micahhausler/container-tx/vendor/github.com/ogier/pflag (vendor tree)
    /usr/local/go/src/github.com/ogier/pflag (from $GOROOT)
    /go/src/github.com/ogier/pflag (from $GOPATH)
compose/compose.go:11:2: cannot find package "gopkg.in/yaml.v2" in any of:
    /go/src/github.com/micahhausler/container-tx/vendor/gopkg.in/yaml.v2 (vendor tree)
    /usr/local/go/src/gopkg.in/yaml.v2 (from $GOROOT)
    /go/src/gopkg.in/yaml.v2 (from $GOPATH)

micahhausler / container-tx

No url found for submodule path 'vendor/github.com/ogier/pflag' in .gitmodules #1