Implement Bazel build

Change-Id: I246cdd00923d36c11a678b250ef6a91a5e433943

BUILD

diff --git a/BUILD b/BUILD
new file mode 100644
index 0000000..d52faf1
--- /dev/null
+++ b/BUILD
@@ -0,0 +1,10 @@
+load('//tools/bzl:plugin.bzl', 'gerrit_plugin')
+
+gerrit_plugin(
+  name = 'commit-message-length-validator',
+  srcs = glob(['src/main/java/**/*.java']),
+  resources = glob(['src/main/resources/**/*']),
+  manifest_entries = [
+    'Gerrit-PluginName: commit-message-length-validator',
+  ],
+)