Add security warning to INSTALL.markdown
Add security warning to INSTALL.markdown

kakra/railscollab,silliemunkie/cpsprojectmanagement,UWC4C/Railscollab,kakra/railscollab,UWC4C/Railscollab,silliemunkie/cpsprojectmanagement,rajeshrsmail/railscollab,rajeshrsmail/railscollab