Set gist visibility via Git push options (#215)

internal/hooks/hook.go

@@ -0,0 +1,24 @@
+package hooks
+
+import (
+	"fmt"
+	"os"
+	"strconv"
+	"strings"
+)
+
+const BaseHash = "0000000000000000000000000000000000000000"
+
+func pushOptions() map[string]string {
+	opts := make(map[string]string)
+	if pushCount, err := strconv.Atoi(os.Getenv("GIT_PUSH_OPTION_COUNT")); err == nil {
+		for i := 0; i < pushCount; i++ {
+			opt := os.Getenv(fmt.Sprintf("GIT_PUSH_OPTION_%d", i))
+			kv := strings.SplitN(opt, "=", 2)
+			if len(kv) == 2 {
+				opts[kv[0]] = kv[1]
+			}
+		}
+	}
+	return opts
+}