Lightsaber expects this env variable to be LARAVEL_ENV

Signed-off-by: Waldemar Figueroa <waldemar@nobox.com>
Added a custom shell script to the provision process.

- Updates package repositories.
- Installs ImageMagick library required by some of our projects.
- Installs latest Gulp and Bower global packages.
- Installs latest Sass gem.

Signed-off-by: Waldemar Figueroa <waldemar@nobox.com>
First version of in-depth documentation to setup Homestead.

Signed-off-by: Waldemar Figueroa <waldemar@nobox.com>