Change Forum navbar item to Questions

The projects navbar should mirror the one on the spring.io website.
Merge pull request #7 from bclozel/forum

Update navbar item "Forum" -> "Questions"
Fix company name and website in footer
Fix "rm -rf" instruictions

Existing copy is wrong because "git rm -rf *" fails if there are any untracked files (e.g. target/). Changed to "git rm -rf `git ls-files`".
Merge pull request #8 from dsyer/patch-1

Fix "rm -rf" instruictions
Gem installation instructions updated

Using "gem install" didn't work for me because of the Gemfile.lock that is in source control (presumably for a reason).
Fix directory name for sample pages
Merge pull request #10 from dsyer/patch-3

Fix directory name for sample pages
Add "gem install bundler" for people using vanilla Ruby
Merge pull request #9 from dsyer/patch-2

Gem installation instructions updated
Merge remote-tracking branch 'gh-pages-upstream/gh-pages' into gh-pages