Homebrew install from a file I want to save my favourite application in a textfile and then install all of them using homebrew later. 

How can I do this ?
This will be a synthesis of three things:


Making a homebrew formula that will dump the Applications you care about into the homebrew location. This will require some ruby knowledge and a short read of the homebrew wiki.
Making a script to copy/shove/move the files from the homebrew location to /Applications or ~/Applications or an alternate destination with administrator permissions
Learning enough about git to grab the tools. You likely won't be able to merge your "formula" with the homebrew repository since it's against their policy to re-distribute software you don't possess the permission (rights) for software code publication.


If you want to do this as a learning exercise, have a great time learning. There are far better tools to package OS X binaries like Package Maker, JAMF's Composer, or Iceberg.

If you were uncertain if homebrew was your best option, I'd start with Iceberg and a tutorial like this to handle the permissions.