jekyll serve --skip-initial-build to docs
Merge remote-tracking branch 'upstream/master' into patch-10
Update README.markdown

Someone added Jekyll to Hakiri for monitoring gems' security. I'm adding a security shield to README.markdown in this commit.
Remove references to the watch command in the sample
Add a note about the separate commands, show an example without the watcher
Clarify instructions
Merge pull request #2954 from chrisfinazzo/remove-explicit-serve-from-docs
Update history to reflect merge of #2954 [ci skip]
Merge pull request #2953 from vasinov/master
Update history to reflect merge of #2953 [ci skip]
Merge pull request #2949 from rusikf/patch-10
Update history to reflect merge of #2949 [ci skip]