Ignore IntelliJ data directory

.ijwb is used by bazel intellij plugin to store build status.
.idea is used by IntelliJ to store information about the project.

Change-Id: I115448466c856fa4c7574df780796b6594e15b9a

.gitignore

diff --git a/.gitignore b/.gitignore
index d11829c..da0519e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@
 .project
 .settings/
 target/
+.idea/
+.ijwb/