Add describetion for makedirs in file

docs/file.rst

@@ -0,0 +1,17 @@
+File
+-------
+
+..  py:function:: pydu.file.makedirs(path, mode=0o755, ignore_errors=False, exist_ok=False)
+
+  Create a leaf directory and all intermediate ones.
+
+    >>> from pydu.file import makedirs
+    >>> makedirs('test/test')
+    >>> makedirs('test/test/test')
+    >>> makedirs('test',exist_ok=True)
+    >>> makedirs('test')
+    Traceback (most recent call last):
+     ...    OSError: Create dir: {} error.
+
+
+