Added example for color usage

Author: poppycompass

README.md

@@ -257,6 +257,37 @@ Hello Someusername
 ```
 
 
+### Output with Color and Bold letters
+If you want to change the output such as coloring and bold letters, you can do as follows(example is using [fatih/color](https://github.com/fatih/color)).
+
+```go
+import "github.com/fatih/color"
+
+cyan := color.New(color.FgCyan).SprintFunc()
+yellow := color.New(color.FgYellow).SprintFunc()
+boldRed := color.New(color.FgRed, color.Bold).SprintFunc()
+shell.AddCmd(&ishell.Cmd{
+    Name: "color",
+    Help: "color print",
+    Func: func(c *ishell.Context) {
+        c.Print(cyan("cyan\n"))
+        c.Println(yellow("yellow"))
+        c.Printf("%s\n", boldRed("bold red"))
+    },
+}
+```
+Output
+```bash
+$ go run main.go
+Sample Interactive Shell
+>>> color
+cyan
+yellow
+bold red
+>>>
+```
+
+
 ### Example
 Available [here](https://github.com/abiosoft/ishell/blob/master/example/main.go).
 ```sh

example/main.go

@@ -8,6 +8,7 @@ import (
 	"time"
 
 	"github.com/abiosoft/ishell"
+	"github.com/fatih/color"
 )
 
 func main() {
@@ -190,6 +191,19 @@ This is another line of it.
 		},
 	})
 
+	cyan := color.New(color.FgCyan).SprintFunc()
+	yellow := color.New(color.FgYellow).SprintFunc()
+	boldRed := color.New(color.FgRed, color.Bold).SprintFunc()
+	shell.AddCmd(&ishell.Cmd{
+		Name: "color",
+		Help: "color print",
+		Func: func(c *ishell.Context) {
+			c.Print(cyan("cyan\n"))
+			c.Println(yellow("yellow"))
+			c.Printf("%s\n", boldRed("bold red"))
+		},
+	})
+
 	// when started with "exit" as first argument, assume non-interactive execution
 	if len(os.Args) > 1 && os.Args[1] == "exit" {
 		shell.Process(os.Args[2:]...)