Add support for Rails 6

[EverybodyKurts]

Now that Rails 6 is released, a version should be released that supports activesupport, ~> 6.0

[skcc321]

actually it rollled back to 0.5.0 version because of dependency on activesupport 5 in 0.7.0 version.

[kapso]

Curious if Rails 6 support is coming out anytime soon? Thanks.

[sahilchopra]

+1