Add Group 6 Translation Doc : PouchContainer volume mechanism analysis

[gtong900]

#24

[zl117]

Some comments from Group 1:
For the long translation

1. Line 1: we normally refers "镜像" to image but not mirror
   the same problem can be found throughout this translation like in line3 ...
2. Line 5: "on the container" -> "in the container"
3. Line 6 : "HOW-TO persistent container data", persistent does not serve as a verb. Should find another way to rephrase this sentence.
4. Line 10: "Moreover volume" normally we have a comma right after the Moreover
5. Line 74: "underly file system" -> normally used with "underlying file system"
   If we are wrong please let us know, thank you!