Give the Rails cache its own Redis namespace

Missing part of active user

Version680

VERSION to 6.8.0

Update Shell version in the Install doc

Allow to overwrite location of gitlab.yml config file.

Allow to specify secret token via SECRET_KEY_BASE environment variable.

Detailed monthly release

Fixes #1190

Fix minor typo in docs

512mb

Most people only care about the 512mb option, we should mention that with one worked you don't get http pushes.

Update title and revert section of 6.7-to-6.8 docs

fix installation.md typo

depency -> dependency

Workflow documentation

Help pages on doc.gitlab.com/ce are missing titles. This needs to be
solved globally.

This text was deleted in 564c37d9.

Update monthly release doc

/cc @sytse @jacobvosmaer @marin

Official location

I got two today:
https://twitter.com/wonderb0lt/status/456545094644936705
https://twitter.com/madpew/status/456758525398884352

Rc1 updates

#1178

Please check it well 😃

If this gets merged, the annotated version tag 6.8.0.rc1 will point to https://dev.gitlab.org/gitlab/gitlabhq/commit/e6b668ab0169f981a5c4162cd8625daf02e6f5a8

/cc @sytse @jacobvosmaer @marin

fix bundle install error