allow playground/ directory for testing stuff

.gitignore

@@ -9,6 +9,7 @@
 /bin/stow
 /doc/stow.info
 /doc/version.texi
+/playground/
 tmp-testing-trees/
 _build/
 autom4te.cache/

CONTRIBUTING.md

@@ -85,6 +85,11 @@ or to run the whole suite:
 However currently there is an issue where this interferes with
 `TEST_VERBOSE`.
 
+If you want to create test files for experimentation, it is
+recommended to put them in a subdirectory called `playground/` since
+this will be automatically ignored by git and the build process,
+avoiding any undesirable complications.
+
 Translating Stow
 ----------------
 

MANIFEST.SKIP

@@ -89,6 +89,7 @@ tmp-testing-trees
 ^.travis.yml
 ^docker/
 ^[a-zA-Z]*-docker.sh
+^playground/
 
 # Avoid development config
 ^.dir-locals.el