Fixed typo in CHANGELOG.md

styling and typo fixes in installation guide

Hipchat service implementation

improve regrex for match(sidekiq) robustness

Fixed typo in Readme.md

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.

Fixed 22th -> 22nd

Fix cancel button link on edit files page