diff --git a/.gitignore b/.gitignore
new file mode 100644
index 0000000..29035da
--- /dev/null
+++ b/.gitignore
@@ -0,0 +1,2 @@
+/build
+/lean_packages
diff --git a/lakefile.lean b/lakefile.lean
new file mode 100644
index 0000000..2f747bb
--- /dev/null
+++ b/lakefile.lean
@@ -0,0 +1,7 @@
+import Lake
+open Lake DSL
+
+package «doc-gen4» {
+  -- add configuration options here
+  supportInterpreter := true
+}
diff --git a/lean-toolchain b/lean-toolchain
new file mode 100644
index 0000000..22206e9
--- /dev/null
+++ b/lean-toolchain
@@ -0,0 +1 @@
+leanprover/lean4:nightly-2021-11-26