Allow for overriding the locale used with the createdb command

Included recipe in Vagrant script and getting this error:

```
createdb: database creation failed: ERROR:  encoding UTF8 does not match locale en_US
DETAIL:  The chosen LC_CTYPE setting requires encoding LATIN1.
```

The solution (for me) was to allow for specifying the locale in the call to createdb.

This is a proposed fix for issue #2.