Improved .gitignore based on github best practices for Ruby repositories.

Author: StefanWallin

.gitignore

@@ -17,3 +17,21 @@
 
 # Don't commit meetup api keys by mistake...
 /.env
+
+# Best practice from GitHub
+/*.gem
+/*.rbc
+/.config
+/coverage
+/InstalledFiles
+/lib/bundler/man
+/pkg
+/rdoc
+/spec/reports
+/test/tmp
+/test/version_tmp
+
+# YARD artifacts
+.yardoc
+_yardoc
+doc/