我安装了正确版本的Bundler：
docker@f5990915a8ae:/usr/src/app$ bundler version
Bundler version 2.2.17 (2021-05-05 commit 69cbd6e10e)
但当我运行db:migrate时，它似乎在使用另一个：
Warning: the running version of Bundler (2.1.4) is older than the version that created the lockfile (2.2.17). We suggest you to upgrade to the version that created the lockfile by running gem install bundler:2.2.17.
这是我的应用程序宝石环境：
RubyGems Environment:
- RUBYGEMS VERSION: 3.1.2
- RUBY VERSION: 2.7.1 (2020-03-31 patchlevel 83) [x86_64-linux-gnu]
- INSTALLATION DIRECTORY: /home/docker/.gem
- USER INSTALLATION DIRECTORY: /home/docker/.gem/ruby/2.7.0
- RUBY EXECUTABLE: /usr/bin/ruby2.7
- GIT EXECUTABLE: /usr/bin/git
- EXECUTABLE DIRECTORY: /home/docker/.gem/bin
- SPEC CACHE DIRECTORY: /home/docker/.gem/specs
- SYSTEM CONFIGURATION DIRECTORY: /etc
- RUBYGEMS PLATFORMS:
- ruby
- x86_64-linux
- GEM PATHS:
- /home/docker/.gem
- /home/docker/.gem/ruby/2.7.0
- /var/lib/gems/2.7.0
- /usr/lib/x86_64-linux-gnu/rubygems-integration/2.7.0
- /usr/share/rubygems-integration/2.7.0
- /usr/share/rubygems-integration/all
- GEM CONFIGURATION:
- :update_sources => true
- :verbose => true
- :backtrace => false
- :bulk_threshold => 1000
- "gem" => "--no-document"
- REMOTE SOURCES:
- https://rubygems.org/
- SHELL PATH:
- /home/docker/.gem//bin
- /home/docker/.gem/ruby/2.7.0/bin
- /usr/local/sbin
- /usr/local/bin
- /usr/sbin
- /usr/bin
- /sbin
- /bin
这是安装的两个捆绑器版本：
home/docker/.gem/specifications/bundler-2.2.17.gemspec
usr/lib/ruby/gems/2.7.0/specifications/default/bundler-2.1.4.gemspec
如何使db:migrate使用正确的数据库？
更改为
bundle exec rake db:migrate
或在Gemfile.lock 中更改捆绑程序版本