Add more documentation.

docs/to-do.md

@@ -0,0 +1,13 @@
+* Test on Windows.
+
+* Implement fixers and a `fix` command.
+
+* Optimize speed and memory usage.
+
+* Document how to install.
+
+* The file pattern `{num1..num2}` is not fully implemented yet. See
+`ConvertWildcardPatternToGoRegexp` in `path_matcher.go`
+
+* Add an example of how to use the `check` command in a continuous integration build or in a Git
+pre-commit hook.