Add LGTM.com code quality badges

diff --git a/README.md b/README.md
index cf62b33e653a08256f4ca05a851d1e104ac0902b..105ac1365d31fc63e60e55c15af394745ea19ef5 100644 (file)
--- a/README.md
+++ b/README.md
@@ -1,4 +1,6 @@
 [![Build Status](https://travis-ci.org/kkos/oniguruma.svg?branch=master)](https://travis-ci.org/kkos/oniguruma)
+[![Code Quality: Cpp](https://img.shields.io/lgtm/grade/cpp/g/kkos/oniguruma.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/kkos/oniguruma/context:cpp)
+[![Total Alerts](https://img.shields.io/lgtm/alerts/g/kkos/oniguruma.svg?logo=lgtm&logoWidth=18)](https://lgtm.com/projects/g/kkos/oniguruma/alerts)
 
 Oniguruma
 =========