gistfile1.txt

production/                
   ansible_hosts         # inventory file for production servers
   group_vars/
      group1                 # here we assign variables to particular groups for production
      group2                 # ""
   host_vars/
      hostname1              # if production systems need specific variables, put them here 
      hostname2              # ""
   files/

staging/
   ansible_hosts         # inventory file for stage environment
   group_vars/           
   host_vars/
   files/

group_vars/
   group1                 # here we assign variables to particular groups
   group2                 # ""
host_vars/
   hostname1              # if systems need specific variables, put them here
   hostname2              # ""
files/
   file1


site.yml                  # master playbook
webservers.yml            # playbook for webserver tier
dbservers.yml             # playbook for dbserver tier

roles/

ansible-playbook -i production/ansible_hosts site.yml
ansible-playbook -i staging/ansible_hosts site.yml