Adds dbshell argument to manage.py command
Adds dbshell argument to manage.py command

Since dbshell argument allows to quickly access db,
let's add this information into Developer Guide.

Closes-Bug: 1384329

Change-Id: If55add68baa3b4a7ea4ddf210b0b034057554059

stackforge/fuel-web,huntxu/fuel-web,nebril/fuel-web,eayunstack/fuel-web,eayunstack/fuel-web,nebril/fuel-web,zhaochao/fuel-web,eayunstack/fuel-web,zhaochao/fuel-web,zhaochao/fuel-web,prmtl/fuel-web,nebril/fuel-web,nebril/fuel-web,eayunstack/fuel-web,nebril/fuel-web,zhaochao/fuel-web,stackforge/fuel-web,SmartInfrastructures/fuel-web-dev,prmtl/fuel-web,zhaochao/fuel-web,SmartInfrastructures/fuel-web-dev,eayunstack/fuel-web,SmartInfrastructures/fuel-web-dev,SmartInfrastructures/fuel-web-dev,SmartInfrastructures/fuel-web-dev,stackforge/fuel-web,prmtl/fuel-web,huntxu/fuel-web,prmtl/fuel-web,huntxu/fuel-web,huntxu/fuel-web,prmtl/fuel-web,huntxu/fuel-web