Added design doc

DESIGN.md

@@ -0,0 +1,29 @@
+# Design Notes
+
+The idea behind `piku` is that it provides the simplest possible way to deploy web apps or services. Simplicity comes at the expense of features, of course, and this document tries to capture the trade-offs.
+
+## uWSGI
+
+Using [uWSGI][uwsgi] in [emperor mode][emperor] gives us the following features for free:
+
+* Python WSGI integration
+* Process monitoring, restarting, basic resource limiting, etc.
+* Basic security scaffolding, beginning with the ability to define `uid´/`gid` on a per-app basis (if necessary)
+
+## Application isolation
+
+Application isolation can be tackled at several levels, the most relevant of which being:
+
+* OS/process isolation
+* Runtime/library isolation
+
+For 1.0, all applications run under the same `uid`, under separate branches of the same filesystem, and without any resource limiting.
+
+Ways to improve upon that (short of full containerisation) typically entail the use of a `chroot` environment (which is available under most POSIX systems in one form or another) or Linux kernel namespaces - both of which are supported by [uWSGI][uwsgi] (which can also handle resource limiting to a degree). 
+
+As to runtime isolation, `piku` only provides `virtualenv` support until 1.0, and all Python apps will use the default interpreter (Go, Node and Java support will share these limitations in each major version).
+
+Supporting multiple Python versions can be done by deploying `piku` again under a different Python or using `pyenv` when building app environments, which makes it a little harder to manage using the same [uWSGI][uwsgi] setup (but not impossible).
+
+[uwsgi]: https://github.com/unbit/uwsgi
+[emperor]: http://uwsgi-docs.readthedocs.org/en/latest/Emperor.html

README.md

@@ -10,6 +10,7 @@ I kept finding myself wanting an Heroku-like way to deploy stuff on a few remote
 
 From the bottom up:
 
+- [ ] Support Node deployments (if at all possible in a sane fashion)
 - [ ] Support Java deployments
 - [ ] Support Go deployments
 - [ ] `chroot` isolation