* initial commit for structure
* migrate Container Lifecycle Hooks and related files to Concepts
* update Concepts ToC
* fix formatting
* Formatting tweaks
* comment out What's next
* remove What's next
* Begin rewrite of container-lifecycle-hooks.md
* incremental update to edit
* Split Container Lifecycle Hooks into container-lifecycle-hooks.md and container-environment.md; change all referring links.
* Add concept template to volumes.md and images.md
* Apply changes for steveperry-53 feedback.
* fix format issue
* tweak formatting
* fix Concepts ToC
* update links
* add back changes to Concepts ToC
* fix a link
* update links
yupengzte
Andrew Chen
tailnode
dongziming
Janet Kuo