Merge pull request #2 from kobsy/dup-env

Avoid modifying POST params on env while checking for CSRF token

lib/omniauth/rails_csrf_protection/token_verifier.rb

@@ -28,7 +28,7 @@ class TokenVerifier
       end
 
       def call(env)
-        @request = ActionDispatch::Request.new(env)
+        @request = ActionDispatch::Request.new(env.dup)
 
         unless verified_request?
           raise ActionController::InvalidAuthenticityToken