我遇到了类似的问题。
我检查了其他网站，并尝试了他们的建议，但是没有用。
然后我尝试了您的建议。
rake db：create：all 和 rake db：migrate 对我有用。谢谢！

I was having a similar problem. I checked different websites and tried what they suggested but didn't work. Then I tried what you suggested. rake db:create:all and rake db:migrate it worked for me. Thank you!