Sort output for instance and diskimage (#494)

* sort diskimage

* sort instance_list.go

cmd/diskimage/disk_image_list.go

@@ -2,6 +2,7 @@ package diskimage
 
 import (
 	"os"
+	"sort"
 
 	"github.com/civo/cli/common"
 	"github.com/civo/cli/config"
@@ -61,6 +62,11 @@ Example: civo diskimage ls -o=custom -f=id,name`,
 			})
 		}
 
+		// Sort the diskImageList by Name
+		sort.Slice(diskImageList, func(i, j int) bool {
+			return diskImageList[i].Name < diskImageList[j].Name
+		})
+
 		ow := utility.NewOutputWriter()
 
 		for _, diskImage := range diskImageList {

cmd/instance/instance_list.go

@@ -2,6 +2,7 @@ package instance
 
 import (
 	"os"
+	"sort"
 	"strconv"
 	"strings"
 	"time"
@@ -58,6 +59,11 @@ If you wish to use a custom format, the available fields are:
 			os.Exit(1)
 		}
 
+		// Sort instances by hostname
+		sort.Slice(instances, func(i, j int) bool {
+			return instances[i].Hostname < instances[j].Hostname
+		})
+
 		ow := utility.NewOutputWriter()
 		for _, instance := range instances {
 			ow.StartLine()