issue #149 - Update README building-from-source part with the gomodul…

[pink-lucifer]

please help review the pr, thanks a lot!

Related issue #149

Proposed changes

Checklist

• I have read the contributing guidelines
• I confirm that this pull request does not address a security vulnerability. If this pull request addresses a security
  vulnerability, I confirm that I got green light (please contact [email protected]) from the maintainers to push the changes.
• I signed the Developer's Certificate of Origin
  by signing my commit(s). You can amend your signature to the most recent commit by using git commit --amend -s. If you
  amend the commit, you might need to force push using git push --force HEAD:<branch>. Please be very careful when using
  force push.
• I have added tests that prove my fix is effective or that my feature works
• I have added necessary documentation within the code base (if appropriate)
• I have documented my changes in the developer guide (if appropriate)

Further comments

Additionally, tested the change offside...

user@hostname:~/go/src/github.com/ory$ go version 
go version go1.11.4 linux/amd64
user@hostname:~/go/src/github.com/ory$ go get -d -u github.com/ory/oathkeeper
user@hostname:~/go/src/github.com/ory$ cd $(go env GOPATH)/src/github.com/ory/oathkeeper
user@hostname:~/go/src/github.com/ory/oathkeeper$
user@hostname:~/go/src/github.com/ory/oathkeeper$ OATHKEEPER_LATEST=$(git describe --abbrev=0 --tags)
user@hostname:~/go/src/github.com/ory/oathkeeper$ echo ${OATHKEEPER_LATEST}
v0.14.2+oryOS.10
user@hostname:~/go/src/github.com/ory/oathkeeper$ git checkout $OATHKEEPER_LATEST
Note: checking out 'v0.14.2+oryOS.10'.

You are in 'detached HEAD' state. You can look around, make experimental
changes and commit them, and you can discard any commits you make in this
state without impacting any branches by performing another checkout.

If you want to create a new branch to retain commits you create, you may
do so (now or later) by using -b with the checkout command again. Example:

  git checkout -b <new-branch-name>

HEAD is now at 62415a1 ci: Fix docker push arguments in publish task
user@hostname:~/go/src/github.com/ory/oathkeeper$ GO111MODULE=on go install \
>     -ldflags "-X github.com/ory/oathkeeper/cmd.Version=$OATHKEEPER_LATEST -X github.com/ory/oathkeeper/cmd.BuildTime=`TZ=UTC date -u '+%Y-%m-%dT%H:%M:%SZ'` -X github.com/ory/oathkeeper/cmd.GitHash=`git rev-parse HEAD`" \
>     github.com/ory/oathkeeper
user@hostname:~/go/src/github.com/ory/oathkeeper$ git checkout master
Previous HEAD position was 62415a1 ci: Fix docker push arguments in publish task
Switched to branch 'master'
Your branch is up to date with 'origin/master'.
user@hostname:~/go/src/github.com/ory/oathkeeper$ $GOPATH/bin/oathkeeper help
A cloud native Access and Identity Proxy

Usage:
  oathkeeper [command]

Available Commands:
  help        Help about any command
  migrate     
  rules       Commands for managing rules
  serve       
  version     Display this binary's version, build time and git hash of this build

Flags:
  -h, --help     help for oathkeeper
  -t, --toggle   Help message for toggle

Use "oathkeeper [command] --help" for more information about a command.
user@hostname:~/go/src/github.com/ory/oathkeeper$ $GOPATH/bin/oathkeeper version
Version:    v0.14.2+oryOS.10
Git Hash:   62415a1c36f6a335f02adf272cb0e50eb1691f89
Build Time: 2019-01-22 15:24:32.839090877 +0800 CST m=+0.004459638
user@hostname:~/go/src/github.com/ory/oathkeeper$ 

[pink-lucifer]

@aeneasr

At your convinience, would you please take a look of the CI issue?

[aeneasr]

Thank you! The CI seems to have some network issues - not a problem!