Add thumbnails guide (draft)
Add installation note for imagemagick on linux
cedar now is the default stack

If we don't explicitly state that cedar is the default stack, the Coaches won't have to explain what stacks are, which probably does not add any value at this point.
Merge pull request #23 from rkh/patch-1

cedar now is the default stack
removed github buttons
Added Berlin app as an extracurricular
Update _posts/2012-04-18-guide.markdown
Expand "rails s" command
Remove mentions of "Command Prompt" text in favor of explanation in header
Change HTML indentation to two spaces
Improve copy in app guide
Merge pull request #25 from norbert/expanded-commands

Expand Rails commands
switch to using RailsInstaller for OSX
ignore readme file for rails installer
Merge pull request #27 from norbert/improved-app-guide-copy

Improve app guide copy
Added localizations
Update index.html
Remove CSS for nonexistent ids and classes

Conflicts:

	_posts/2012-04-18-app.markdown
Update index.html
Update _posts/2012-04-18-app.markdown

Fixed link to Guide 3