Title: Application Port Forwarding

Describe the issue:

If you want to enable port-forwarding to a gear, the default examples shown in the current documentation only show you how to get forwarded to the Head gear, and any attached Databased. 

However if you run:

   # rhc port-forward eap -g 54401bb67f116a704e000169

You can get forwarded to any gear in your environment. 


Suggestions for improvement:

Explain / update the documentation to explain this -g option. 

Additional information:

Currently Portforarding for a gear does the following: 

# Collect locally bound ports
declare -A $(/usr/sbin/lsof -iTCP -sTCP:LISTEN -P 2> /dev/null | /bin/awk '/LISTEN/{ print "local_bindings["$9"]="$1 }')

# Extract database ports out of the environment
declare -A remote_bindings

for host_var in $(env | grep _DB_HOST | awk -F '=' '{print $1}'); do
    db_name=$(echo $host_var |sed -e 's/.*OPENSHIFT_\(.*\)_DB_HOST/\1/' |tr '[A-Z]' '[a-z]')
    port_var=$(echo $host_var |sed 's/_DB_HOST/_DB_PORT/')
    port_val=$(echo ${!port_var})
    host_val=$(echo ${!host_var})
    db_binding="${host_val}:${port_val}"
    remote_bindings[$db_binding]=${db_name}
done
    
# Merge the database ports into the local binding list; if the databases are
# local, the keys will simply be overwritten in the array
if ! $exclude_remote ; then
  for remote_binding in "${!remote_bindings[@]}"; do
    local_bindings[$remote_binding]="${remote_bindings[$remote_binding]}"
  done
fi

In short:

- you get a listing of ports seen by the gear
- Find out if you have a database mapping
  - Determine if its scaled
- Merge duplicates
- Report on the ports for rhc to setup mappings.