Creating a Blog in an Existing Ruby on Rails app

You can integrate a jekyll style blog with markdown files for blog posts very easily using the rails engine Postmarkdown.

Edit: Updated URL.

To integrate WP, install Wordpress in a subdirectory, like /blog. So you'd have http://arenpatel.com/blog. Make the WP blog's home page the index / front page of the WP installation. You would have to manually port your layout in some shape or fashion into the WP theme. I can't think of a good way to share that, especially any dynamic code. You could share the same css using an @import statement in the WP theme's style.css (a required file). Wordpress works fine in this screnario.

I don't think there is anything in the Ruby world that does everything WP does, but maybe that's not necessary in your case???

Im not sure how well php and ruby play together under the same directory so theeasies way i see is to host a Wordpress blog under a subdomain, for example, http://blog.arenpatel.com/.

You will of course have to write you own (or alter an existing) theme for wordpress in order to make it look the way your rails app does.You can read all about it here: http://codex.wordpress.org/Theme_Development

As for your twitter feed; there are a bunch of plugins for wordpress do the same thing. All you will have to do is to style it via css.

Cheers!