Add rultor configuration

This allows merging via github comments. The comment `@rultor merge`
will execute the script (which currently doesn't do anything) and if it
succeeds will perform the merge.

I plan to use rultor later for:
 * Automatic deployment to PyPI (development releases directly from
   master, we do this already in coala, see
   https://github.com/coala-analyzer/coala/blob/master/.rultor.yml)
 * Automatic releasing with deployment to PyPI.
 * Veryfy that all CI services pass before merging (see
   https://github.com/yegor256/rultor/issues/869)

With this any manual pushes to master are disallowed, all pushes to
master have to be validated by continuous integration and reviewed by a
non-committer.

diff --git a/.rultor.yml b/.rultor.yml
new file mode 100644 (file)
index 0000000..0871296
--- /dev/null
+++ b/.rultor.yml
@@ -0,0 +1,2 @@
+merge:
+  script: echo "Nothing to do (yet)."