Add specs for RemoteStorageAuthorization model

spec/support/helpers/redis_helper.rb

@@ -0,0 +1,8 @@
+def redis_rs
+  @redis_rs ||= Redis.new(url: Setting.rs_redis_url)
+end
+
+def redis_rs_delete_keys(pattern)
+  keys = redis_rs.keys(pattern)
+  redis_rs.del(*keys)
+end