Configure email sender (see #250) to '[email protected]'

[bellef]

Fix for #250
@sophiedeziel is it ok to put your email here?

[coveralls]

Coverage decreased (-1.5%) to 98.438% when pulling 4119bf3 on bellef:fix/mailer_sender into b6b70a6 on montrealrb:master.

[xymbol]

You should never put actual email addresses in an open source project. Say someone rewrites a test and inadvertently sends 1,000 emails using that address?

[sophiedeziel]

I think you should reopen that pull-request, but using an environment variable instead of a string. That way, it's a matter of configuration on the prod server.