Implement show flag for configure command

If someone wants to see what they've currently got configured, they
should not have to eyeball the actual config files.

cmd/configure.go

@@ -1,6 +1,10 @@
 package cmd
 
 import (
+	"fmt"
+	"os"
+	"text/tabwriter"
+
 	"github.com/exercism/cli/config"
 	"github.com/spf13/cobra"
 	"github.com/spf13/viper"
@@ -26,29 +30,41 @@ You can also override certain default settings to suit your preferences.
 `,
 	Run: func(cmd *cobra.Command, args []string) {
 		usrCfg := config.NewEmptyUserConfig()
-
 		err := usrCfg.Load(viperUserConfig)
 		BailOnError(err)
 
-		err = usrCfg.Write()
+		apiCfg := config.NewEmptyAPIConfig()
+		err = apiCfg.Load(viperAPIConfig)
 		BailOnError(err)
 
-		apiCfg := config.NewEmptyAPIConfig()
+		show, err := cmd.Flags().GetBool("show")
+		BailOnError(err)
 
-		err = apiCfg.Load(viperAPIConfig)
+		if show {
+			w := tabwriter.NewWriter(os.Stdout, 0, 0, 2, ' ', 0)
+			defer w.Flush()
+
+			fmt.Fprintln(w, "")
+			fmt.Fprintln(w, fmt.Sprintf("Config dir:\t%s", config.Dir()))
+			fmt.Fprintln(w, fmt.Sprintf("-t, --token\t%s", usrCfg.Token))
+			fmt.Fprintln(w, fmt.Sprintf("-w, --workspace\t%s", usrCfg.Workspace))
+			fmt.Fprintln(w, fmt.Sprintf("-a, --api\t%s", apiCfg.BaseURL))
+			return
+		}
+
+		err = usrCfg.Write()
 		BailOnError(err)
 
 		err = apiCfg.Write()
 		BailOnError(err)
-
-		return
 	},
 }
 
 func initConfigureCmd() {
 	configureCmd.Flags().StringP("token", "t", "", "authentication token used to connect to exercism.io")
 	configureCmd.Flags().StringP("workspace", "w", "", "directory for exercism exercises")
 	configureCmd.Flags().StringP("api", "a", "", "API base url")
+	configureCmd.Flags().BoolP("show", "s", false, "show the current configuration")
 
 	viperUserConfig = viper.New()
 	viperUserConfig.BindPFlag("token", configureCmd.Flags().Lookup("token"))