diff --git a/build-android/.gitkeep b/build-android/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/build-windows/.gitkeep b/build-windows/.gitkeep
new file mode 100644
index 0000000..e69de29
diff --git a/doc/.gitkeep b/doc/.gitkeep
new file mode 100644
index 0000000..e69de29