Exclude intellij files from git

Add gitignore file and exclude intellij files.

Change-Id: I0847fe078c7eb5f29129dfc35beb50b3dee03203

.gitignore

diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..8cdcd0b
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,3 @@
+# IntelliJ files
+.idea
+*.iml
\ No newline at end of file