add requirements.txt

Also install requirements in .travis.yml.

By the way, I explored ways to install Pandoc in a Travis container
environment (without sudo), but that's just too hard. Giving up.

1 files changed, 2 insertions, 1 deletions

diff --git a/pyblog b/pyblog
index 5f318258..f993172d 100755
--- a/pyblog
+++ b/pyblog
@@ -810,7 +810,8 @@ def main():
     """CLI interface."""
     description = "Simple blog generator in Python with Pandoc as backend."
     parser = argparse.ArgumentParser(description=description)
-    subparsers = parser.add_subparsers()
+    subparsers = parser.add_subparsers(dest="action")
+    subparsers.required = True
 
     parser_new_post = subparsers.add_parser(
         "new_post", aliases=["n", "new"],