Refactor cli (#52)

* docs: Update readme, add demo

* refactor: cmd to make it more posix

* chore(deps): Add missed tool

Author: obalunenko

.github/images/demo_1.png

@@ -94,7 +94,7 @@ This repository contains solutions for puzzles and cli tool to run solutions to
   <summary>2017</summary>  
 
   - [x] [Day 1: Inverse Captcha](https://adventofcode.com/2017/day/1)
-  - [ ] [Day 2: Corruption Checksum](https://adventofcode.com/2017/day/2)
+  - [x] [Day 2: Corruption Checksum](https://adventofcode.com/2017/day/2)
   - [ ] [Day 3: Spiral Memory](https://adventofcode.com/2017/day/3)
   - [ ] [Day 4: High-Entropy Passphrases](https://adventofcode.com/2017/day/4)
   - [ ] [Day 5: A Maze of Twisty Trampolines, All Alike](https://adventofcode.com/2017/day/5)
@@ -223,7 +223,27 @@ and execute
 
 Run it and follow instructions
 
+Cli support optional metrics, to enable them you can use following flags:
+
+```text
+    --elapsed, -e  Enables elapsed time metric
+    --bench, -b    Enables benchmark metric
+```
+
+All available flags:
+
+```text
+    COMMANDS:
+       help, h  Shows a list of commands or help for one command
+
+    GLOBAL OPTIONS:
+       --elapsed, -e  Enables elapsed time metric (default: false)
+       --bench, -b    Enables benchmark metric (default: false)
+       --help, -h     show help (default: false)
+       --version, -v  print the version (default: false)
+```
+
+
 ### Demo
 
-![cli demo_step_1](.github/images/demo_1.png)
-![cli demo_step_2](.github/images/demo_2.png)
+[![asciicast](https://asciinema.org/a/9UFklCUVZTQHCRsHD2vybTlMb.svg)](https://asciinema.org/a/9UFklCUVZTQHCRsHD2vybTlMb)

.github/images/demo_2.png

@@ -0,0 +1,41 @@
+package main
+
+import (
+	"context"
+
+	"github.com/urfave/cli/v2"
+)
+
+func commands(ctx context.Context) []*cli.Command {
+	const (
+		cmdRun = "run"
+	)
+
+	cmds := []*cli.Command{
+		{
+			Name:                   cmdRun,
+			Aliases:                nil,
+			Usage:                  "Runs advent-of-code application",
+			UsageText:              "",
+			Description:            "",
+			ArgsUsage:              "",
+			Category:               "",
+			BashComplete:           nil,
+			Before:                 nil,
+			After:                  nil,
+			Action:                 menu(ctx),
+			OnUsageError:           nil,
+			Subcommands:            nil,
+			Flags:                  cmdRunFlags(),
+			SkipFlagParsing:        false,
+			HideHelp:               false,
+			HideHelpCommand:        false,
+			Hidden:                 false,
+			UseShortOptionHandling: false,
+			HelpName:               "",
+			CustomHelpTemplate:     "",
+		},
+	}
+
+	return cmds
+}

README.md

@@ -0,0 +1,48 @@
+package main
+
+import (
+	"github.com/urfave/cli/v2"
+)
+
+const (
+	flagElapsed        = "elapsed"
+	flagShortElapsed   = "e"
+	flagBenchmark      = "bench"
+	flagShortBenchmark = "b"
+)
+
+func cmdRunFlags() []cli.Flag {
+	var res []cli.Flag
+
+	elapsed := cli.BoolFlag{
+		Name:        flagElapsed,
+		Aliases:     []string{flagShortElapsed},
+		Usage:       "Enables elapsed time metric",
+		EnvVars:     nil,
+		FilePath:    "",
+		Required:    false,
+		Hidden:      false,
+		Value:       false,
+		DefaultText: "",
+		Destination: nil,
+		HasBeenSet:  false,
+	}
+
+	benchmark := cli.BoolFlag{
+		Name:        flagBenchmark,
+		Aliases:     []string{flagShortBenchmark},
+		Usage:       "Enables benchmark metric",
+		EnvVars:     nil,
+		FilePath:    "",
+		Required:    false,
+		Hidden:      false,
+		Value:       false,
+		DefaultText: "",
+		Destination: nil,
+		HasBeenSet:  false,
+	}
+
+	res = append(res, &elapsed, &benchmark)
+
+	return res
+}