Added database connectivity
Updated to use APP_ENV if available
Merge pull request #26 from phpmentoring/database

Added database connectivity
Move index to the site directory and rename it with a php extension.
Merge pull request #30 from phpmentoring/move-index

Move index to the site directory and rename it with a php extension.
Merge branches 'master' and 'tags' of github.com:phpmentoring/mentor-app into tags