Proposal to fix oauth 2.0 incompatibility

[uzzer]

https://github.com/simi/omniauth-facebook/issues/363 it is written we can not do anything, but We can lock 'omniauth-oauth2' to <=1.7.0 (latest with pre 2.0 omniauth) until omniauth-facebook support omniauth 2.0

ty for broken master :)

[swiknaba]

• You can lock omniauth in your own Gemfile to a specific version. Just add omniauth to your Gemfile with any version you like. Install it using bundler, then add facebook-omniauth and run bundler again. That will install and lock the correct versions for you.

• Constraining this gem is a breaking change (!).

• I'm using this gem with omniauth 2.0 without problems. So not sure what you and the issue opener are doing different or wrong. If I get some time, I can share my exact setup (I'm slow though and it is not in any public repo).

• this is not a "fix", you just lock the version of a dependency, so the PR description is misleading. Also, this lock is increasing the restrictions, allowing less, not more. Anything possible after that PR is already possible now.