Add zsh shell completion script

spring-boot-cli/src/main/content/INSTALL.txt

@@ -26,6 +26,15 @@ set SPRING_HOME to point to a specific installation.  You should also add SPRING
 to your PATH environment variable.
 
 
+Shell Completion
+----------------
+Shell auto-completion scripts are provided for BASH and ZSH. Add symlinks to the appropriate
+location for your environment. For example, something like:
+
+  ln -s ./shell-completion/bash/spring /etc/bash_completion.d/spring
+  ln -s ./shell-completion/zsh/_spring /usr/local/share/zsh/site-functions/_spring
+
+
 Checking Your Installation
 --------------------------
 To test if you have successfully install the CLI you can run the following command:

spring-boot-cli/src/main/content/shell-completion/zsh/_spring

@@ -0,0 +1,29 @@
+#compdef spring 'spring'
+#autoload
+
+_spring() {
+
+	local cword
+	let cword=CURRENT-1
+
+	local hints
+	hints=()
+
+	local reply
+	while read -r line; do
+		reply=`echo "$line" | awk '{printf $1 ":"; for (i=2; i<NF; i++) printf $i " "; print $NF}'`
+		hints+=("$reply")
+	done < <(spring hint ${cword} ${words[*]})
+
+	if ((cword == 1)) {
+		_describe -t commands 'commands' hints
+		return 0
+	}
+
+	_describe -t options 'options' hints
+	_files
+
+	return 0
+}
+
+_spring "$@"