Use hostnames everywhere in docs, add YAML note and deprecate env.md

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>
Default link alias which is just the service name

Closes #37.

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>
Update docs to remove numeric suffix

Signed-off-by: Aanand Prasad <aanand.prasad@gmail.com>
Merge pull request #364 from docker/non-numeric-link-alias

Non-numeric link alias