Add documentation and .gem file to .gitignore

This adds 
*.gem
doc/
.yardoc/
Update website and meta in the readme

There's not much point for outdated information
Merge pull request #2 from najamelan/hotfix/ignoreDocs

Add documentation and .gem file to .gitignore
Merge pull request #3 from najamelan/hotfix/outdatedReadme

Update website and meta in the readme
Improve work with requirements. Remove circular dependency and some "require rubygems"
Add development group to Gemfile