Add tab completion to bundler plugin.

plugins/bundler/_bundler

+#compdef bundle
+
+local curcontext="$curcontext" state line _gems _opts ret=1
+
+_arguments -C -A "-v" -A "--version" \
+	'(- 1 *)'{-v,--version}'[display version information]' \
+	'1: :->cmds' \
+	'*:: :->args' && ret=0
+
+case $state in
+	cmds)
+		_values "bundle command" \
+			"install[Install the gems specified by the Gemfile or Gemfile.lock]" \
+			"update[Update dependencies to their latest versions]" \
+			"package[Package the .gem files required by your application]" \
+			"exec[Execute a script in the context of the current bundle]" \
+			"config[Specify and read configuration options for bundler]" \
+			"check[Determine whether the requirements for your application are installed]" \
+			"list[Show all of the gems in the current bundle]" \
+			"show[Show the source location of a particular gem in the bundle]" \
+			"console[Start an IRB session in the context of the current bundle]" \
+			"open[Open an installed gem in the editor]" \
+			"viz[Generate a visual representation of your dependencies]" \
+			"init[Generate a simple Gemfile, placed in the current directory]" \
+			"gem[Create a simple gem, suitable for development with bundler]" \
+			"help[Describe available tasks or one specific task]"
+		ret=0
+		;;
+	args)
+		case $line[1] in
+			help)
+				_values 'commands' \
+                    'install' \
+                    'update' \
+                    'package' \
+                    'exec' \
+                    'config' \
+                    'check' \
+                    'list' \
+                    'show' \
+                    'console' \
+                    'open' \
+                    'viz' \
+                    'init' \
+                    'gem' \
+                    'help' && ret=0
+				;;
+			install)
+				_arguments \
+					'(--no-color)--no-color[disable colorization in output]' \
+					'(--local)--local[do not attempt to connect to rubygems.org]' \
+					'(--quiet)--quiet[only output warnings and errors]' \
+					'(--gemfile)--gemfile=-[use the specified gemfile instead of Gemfile]:gemfile' \
+					'(--system)--system[install to the system location]' \
+					'(--deployment)--deployment[install using defaults tuned for deployment environments]' \
+					'(--frozen)--frozen[do not allow the Gemfile.lock to be updated after this install]' \
+					'(--path)--path=-[specify a different path than the system default]:path:_files' \
+					'(--binstubs)--binstubs=-[generate bin stubs for bundled gems to ./bin]:directory:_files' \
+					'(--without)--without=-[exclude gems that are part of the specified named group]:groups'
+				ret=0
+				;;
+			exec)
+				_normal && ret=0
+				;;
+			(open|show)
+				_gems=( $(bundle show 2> /dev/null | sed -e '/^  \*/!d; s/^  \* \([^ ]*\) .*/\1/') )
+				if [[ $_gems != "" ]]; then
+					_values 'gems' $_gems && ret=0
+				fi
+				;;
+			*)
+				_opts=(  $(bundle help $line[1] | sed -e '/^  \[-/!d; s/^  \[\(-[^=]*\)=.*/\1/') )
+				_opts+=( $(bundle help $line[1] | sed -e '/^  -/!d; s/^  \(-.\), \[\(-[^=]*\)=.*/\1 \2/') )
+				if [[ $_opts != "" ]]; then
+					_values 'options' $_opts && ret=0
+				fi
+				;;
+		esac
+		;;
+esac
+
+return ret

plugins/bundler/bundler.plugin.zsh

+fpath=($ZSH/plugins/bundler $fpath)
+autoload -U compinit
+compinit -i
+
 alias be="bundle exec"
 alias bi="bundle install"
 alias bu="bundle update"