update .gitignore for basically rubyist enviroment.

Most contributors don't need clojure's environment and don't have it.

.gitignore

@@ -1,16 +1,24 @@
-/target
-/classes
-/checkouts
-pom.xml
-*.jar
-*.class
-.lein-deps-sum
-.lein-failures
-.lein-plugins
-/build
-.DS_Store
-*.clj
-.rvmrc
 *.gem
+*.rbc
+.bundle
+.config
+.yardoc
+Gemfile.lock
+InstalledFiles
+_yardoc
+coverage
+doc/
+lib/bundler/man
+pkg
+rdoc
+spec/reports
+test/tmp
+test/version_tmp
+tmp
+
+/build
 .repl_history
-.dat*
+.rvmrc
+.ruby-gemset
+.ruby-version
+.DS_Store