Security: keep the Rails secret token out of version control.

Store the secret token in a .gitignored file called ".secret", which is
created by the initializer if it doesn't exist.

Fix cancel button link on edit files page

changed Gitlab to GitLab in user facing locations

Fix small typo in install docs, Closes #3723

Typo fixes in cleanup.md

Typo fix in database.md closes 3984

Fixed grammatical error.

Issues bulk update