diff --git a/Rails.gitignore b/Rails.gitignore
index 2c74f70f..b4be5c7b 100644
--- a/Rails.gitignore
+++ b/Rails.gitignore
@@ -3,9 +3,6 @@
 .sass-cache
 capybara-*.html
 .rspec
-.rvmrc
-/.bundle
-/vendor/bundle
 /log
 /tmp
 /db/*.sqlite3
@@ -16,3 +13,13 @@ capybara-*.html
 rerun.txt
 pickle-email-*.html
 config/initializers/secret_token.rb
+
+## Environment normalisation:
+/.bundle
+/vendor/bundle
+
+# these should all be checked in to normalise the environment:
+# Gemfile.lock, .ruby-version, .ruby-gemset
+
+# unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
+.rvmrc
diff --git a/Ruby.gitignore b/Ruby.gitignore
index 560d1a6a..b20c5ce6 100644
--- a/Ruby.gitignore
+++ b/Ruby.gitignore
@@ -1,18 +1,29 @@
 *.gem
 *.rbc
-.bundle
 .config
 coverage
 InstalledFiles
-lib/bundler/man
-pkg
-rdoc
-spec/reports
-test/tmp
-test/version_tmp
-tmp
+/pkg/
+/spec/reports
+/test/tmp
+/test/version_tmp
+/tmp/
 
-# YARD artifacts
-.yardoc
-_yardoc
-doc/
+## Documentation cache and generated files:
+/.yardoc
+/_yardoc
+/doc/
+/rdoc
+
+## Environment normalisation:
+/.bundle
+/lib/bundler/man
+
+# for a library or gem, you might want to ignore these files since the code is
+# intended to run in multiple environments; otherwise, check them in:
+# Gemfile.lock
+# .ruby-version
+# .ruby-gemset
+
+# unless supporting rvm < 1.11.0 or doing something fancy, ignore this:
+.rvmrc