See #32
gotenv can read simple yaml file so we don't need to use a read yaml
parse.
The value in forego file will be set as default value, if we set flag
or env value, it will override the value in forego file
Read the `PORT` from the system environment if it's present. This is
related to #44 and will make the port read order this:
1. `-p` flag.
2. `PORT` in the `.env` file
3. `PORT` environment variable
4. 5000 as default port
Daniel PerezandDavid Dollar
Võ Anh DuyandDavid Dollar
Nicolás Hock Isaza
Sergio BoteroandDavid Dollar
Jason Wilder