Remove deprecated alias_method_chain.

[one-more-alex]

Rails 6 requires this.

[aarona]

@one-more-alex I fixed this is my fork after I fixed it to support Rails 5. I need to use this gem again and I'm going to fix it support rails 6 now because there are unrelated errors to this PR. If you're interested, would you like to help contribute to my fork? Other people are using it because it supports Rails 5. I'm going to contact platform45 and ask them if I get the rights to push changes to rubygems.org

Let me know if you'd like to help maintain it.

[one-more-alex]

@aarona Thank you for proposition. I am interesting to continue use this gem in Rails 6.
I may try to devote a time to your fork. It will be great to see some redirection or deprecation warning on this gem. Or even merge your work to here.

[aarona]

Those deprecation warnings are gone. There is an issue with migration generators but I've fixed that but haven't pushed the changes yet. I emailed platform45 (hi@platform45.com) 3 days ago and haven't heard anything back yet regarding transferring ownership so if I don't hear from them soon, I'm going to create a new hosted gem at rubygems.org so that people don't have to reference my github repo to get all the latest fixes.

Some of the additions I'd like to add are:

1. a without_role scope (I'm working on this right now)
2. Better rails g easy_roles functionality. (Ability to insert easy_roles :roles into an existing model if it exists.
3. For fun add a new storage method. We have serialize and bitmask but maybe we could support json?

Let me know what you think and if you have any ideas.