create companies controller
implement index action of companies
test for get index rendering index view
implement show action of companies
test for get show renders show view
implement new action for companies
test new action renders new template
implement create action of companies
test for redirecting to company #show after create
test new company does not save to database with invalid attributes
test if company with invalid attributes re render new template
implement edit action for companies
test if edit action renders edit template
implement update action for companies
test if update changes company's attributes
test update company directs to company show
test update does not change company attributes with invalid attributes
invalid update attributes for company renders edit template test
implement destroy action for companies
test destroy action redirects to company index