add .gitignore
diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..45b52f4
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,5 @@
+*.sw?
+sim-applet/build
+sim-applet/test
+.sim-keys*
+sim-keys*