[ext storage] Document the $user feature

[PVince81]

There is a neat hidden feature in external storages: you can use "$user" in any option and it will be replaced by the current user.

For example:

1. create SFTP mount and make it point to some server
2. set "/home/$user/" as root path
3. select "all users"

It will resolve the root path to the current user's user name when mounting.

Documentation is missing for that (I just saw it in the code)

[vgezer]

@PVince81 Do you think this should be added here or also user documentation?
http://doc.owncloud.org/server/6.0/admin_manual/apps/files_external/index.html

[PVince81]

@wakeup I guess putting it only in the admin doc makes more sense, because the $user part doesn't make sense for a single user.

[vgezer]

@PVince81 Any idea what happened to this commit and the file?

[PVince81]

Looks like you submitted it as PR #335
According to its last comment it needs to be forwarded ported to master (or stable7 if the branch was made).

Can you make another PR for that ?

[vgezer]

I cannot find the file mentioned there. Can we just add it somewhere in external mount topic?

[PVince81]

Maybe the page structure has changed since stable6 ?
If you think so, then like you said the message could be put in the most relevant page.
Can you submit a PR for that ?
Thanks.