我正在尝试使用以下命令创建数据库：
bundle exec rake db:create
但是，该命令与所有其他数据库命令一起缺失。我收到的错误是：
rake aborted!
Don't know how to build task 'db:create' (See the list of available tasks with `rake --tasks`)
/root/.rbenv/versions/2.6.1/bin/bundle:23:in `load'
/root/.rbenv/versions/2.6.1/bin/bundle:23:in `<main>'
(See full trace by running task with --trace)
当我这样做时rake -T，我得到以下输出：
rake about # List versions of all Rails frameworks and the environment
rake app:template # Applies the template supplied by LOCATION=(/path/to/template) or URL
rake app:update # Update configs and some other initially generated files (or use just update:configs or update:bin)
rake assets:clean[keep] # Remove old compiled assets
rake assets:clobber # Remove compiled assets
rake assets:environment # Load asset compile environment
rake assets:precompile # Compile all the assets named in config.assets.precompile
rake cache_digests:dependencies # Lookup first-level dependencies for TEMPLATE (like messages/show or comments/_comment.html)
rake cache_digests:nested_dependencies # Lookup nested dependencies for TEMPLATE (like messages/show or comments/_comment.html)
rake dev:cache # Toggle development mode caching on/off
rake initializers # Print out all defined initializers in the order they are invoked by Rails
rake log:clear # Truncates all/specified *.log files in log/ to zero bytes (specify which logs with LOGS=test,deve...
rake middleware # Prints out your Rack middleware stack
rake notes # Enumerate all annotations (use notes:optimize, :fixme, :todo for focus)
rake notes:custom # Enumerate a custom annotation, specify with ANNOTATION=CUSTOM
rake restart # Restart app by touching tmp/restart.txt
rake routes # Print out all defined routes in match order, with names
rake secret # Generate a cryptographically secure secret key (this is typically used to generate a secret for c...
rake stats # Report code statistics (KLOCs, etc) from the application or engine
rake test # Runs all tests in test folder except system ones
rake test:db # Run tests quickly, but also reset db
rake test:system # Run system tests only
rake time:zones[country_or_offset] # List all time zones, list by two-letter country code (`rails time:zones[US]`), or list by UTC off...
rake tmp:clear # Clear cache, socket and screenshot files from tmp/ (narrow w/ tmp:cache:clear, tmp:sockets:clear,...
rake tmp:create # Creates tmp directories for cache, sockets, and pids
rake yarn:install # Install all JavaScript dependencies as specified via Yarn
Ruby version: 2.6.1p33
Rails version: 5.2.2
我怎样才能解决这个问题？