2013年11月当時の.gitignore http://railstutorial.jp/chapters/beginning?version=4.0#code-gitignoreand more.

.gitignore

# See http://help.github.com/ignore-files/ for more about ignoring files.
#
# If you find yourself ignoring temporary files generated by your text editor
# or operating system, you probably want to add a global ignore instead:
#   git config --global core.excludesfile '~/.gitignore_global'

# Ignore bundler config.
/.bundle

# Ignore the default SQLite database.
/db/*.sqlite3
/db/*.sqlite3-journal

# Ignore all logfiles and tempfiles.
/log/*.log
/tmp

# Ignore other unneeded files.
/vendor/bundle/
doc/
*.swp
*~
.project
.DS_Store
.idea
.secret