feat: skip running cob (#19)

README.md

@@ -236,6 +236,17 @@ Comparison
 
 </details>
 
+## Skip running cob
+If your commit message contains `[skip cob]`, cob is skipped.
+
+```
+$ git add README.md
+$ git commit -m "[skip cob] update README.md"
+$ cob
+2020/04/19 12:46:57 [skip cob] is detected, so the benchmark is skipped
+```
+
+
 # Usage
 
 ```

main.go

@@ -9,14 +9,13 @@ import (
 	"os/exec"
 	"strings"
 
-	"gopkg.in/src-d/go-git.v4/plumbing"
-
 	"golang.org/x/xerrors"
+	git "gopkg.in/src-d/go-git.v4"
+	"gopkg.in/src-d/go-git.v4/plumbing"
 
 	"github.com/olekukonko/tablewriter"
 	"github.com/urfave/cli/v2"
 	"golang.org/x/tools/benchmark/parse"
-	"gopkg.in/src-d/go-git.v4"
 )
 
 type result struct {
@@ -87,6 +86,16 @@ func run(c config) error {
 		return xerrors.Errorf("unable to get the reference where HEAD is pointing to: %w", err)
 	}
 
+	commit, err := r.CommitObject(head.Hash())
+	if err != nil {
+		return xerrors.Errorf("unable to get the head commit: %w", err)
+	}
+
+	if strings.Contains(strings.ToLower(commit.Message), "[skip cob]") {
+		log.Println("[skip cob] is detected, so the benchmark is skipped")
+		return nil
+	}
+
 	prev, err := r.ResolveRevision(plumbing.Revision(c.base))
 	if err != nil {
 		return xerrors.Errorf("unable to resolves revision to corresponding hash: %w", err)