Document basic git functionality.

doc/utils.md

@@ -162,6 +162,24 @@ Converts given number to a string with two-digit fractional
 part. Should the fractional part be 0, it is replaced with the string
 "--".
 
+### Git
+
+    (import util-git)
+
+This module provides basic git repository querying functionality.
+
+    (git repo [mode])
+
+* ```repo``` - a path to repository
+* ```mode``` - return values mode for operations
+
+Returns a procedure that allows invocation of git in given ```repo```
+repository returning one or two values based on ```mode``` given:
+
+* ```#:exit``` - returns exit code
+* ```#:output``` - returns the output lines (default)
+* ```#:exit+output``` - returns both exit code and output lines
+
 ### IO
 
     (import util-io)