Developing an app - questions on gems & functionality.

Hi Railsforum!

I've been a lurker here for quite some time, and have finally decided to join. I'm in the process of building a rails application, and think that I have all the necessary requirements figured out. First off, thanks for all your help, and for the forums as well!

What I'd like to do is create a website with a public front end, and a backend accessed by users, brokering the transaction between these users.

Requirements:
-Paypal Adaptive payments.
-Application served between header and footer. (static navigation bars).

I'd like to build the app on Twitter Bootstrap for HTML/CSS, and have the top navigation and footer remain constant, with the rails app served in between - where all static html pages, user pages, etc served between the header and footer of the application.

Users:
-Two types: requesters and producers, although one user can be both roles.
-Stats available to be listed.
-Messaging functionality.
-Commenting between users.
-Editing of profile
-Adding and distribution of funds.
-View requester's listings.
-View producer's completed tasks.
-Approval, rejection, or notes of tasks.

I will need to use paypal adaptive payments to help broker transactions from requesters and producers.

Admin:
-I would like to have an admin backend to oversee the transactions between producers and requesters, add in mailing for signup and notifications, a stats page to view stats, editing of profile, adding funds for users, as well as user messaging. Also, I'd like to keep a watch on the funds.

Deployment:
-I am open to any type of environment, but what security would I need?

My questions are:
-Am I going about this the right way? Am I missing anything? What Gems/Rails Templates would you suggest?

I know that I will need to have a user authentication, which I believe Devise can work well. It would be nice to also have OAuth to allow Google/Facebook connect users to join, but it is not necessary. I've been trying to build it off of https://github.com/RailsApps/rails3-boo … ise-cancan , but have been running into issues.

I've done a lot of research into how I want it built, just want to make sure I'm moving forward correctly.