Showing tmp folder in Rubymine

I have been using RubyMine for a few months now. I must say it has served me well. Recently, I was writing and reading files in the /tmp folder of root directory of my Rails project. However, in my project pane, it was not showing the /tmp folder. So, I had to go to the folder using my file manager and check the files. When I was through with my task, I wanted to figure out why that folder was not shown in the project pane. Getting the folder to show up was easy. In the project settings, in "Project Structure" section, there is a list of excluded folders. We just have to remove the entry for the /tmp folder.