update ignore rules

Author: yeliulee

.gitignore

@@ -126,6 +126,7 @@ hs_err_pid*
 # Covers JetBrains IDEs: IntelliJ, RubyMine, PhpStorm, AppCode, PyCharm, CLion, Android Studio, WebStorm and Rider
 # Reference: https://intellij-support.jetbrains.com/hc/en-us/articles/206544839
 
+.idea
 # User-specific stuff
 .idea/**/workspace.xml
 .idea/**/tasks.xml