Symlink redis to /usr/bin

[izolate]

As far as I can tell, both redis-cli and redis-server aren't symlinked to /usr/bin during install. Is there any reasoning behind this?

[DavidWittman]

@izolate Yes... this role was originally using the alternatives module to handle this, but was removed due to a regression discovered in #50.

I'm confident the issue has been addressed though and the alternatives should be brought back in.