railsとrakeの違い。なぜ同じ処理をするのにコマンドが２つあるのか？（rake db:migrateとrails db:migrateの違い）

rake db:migrate
rails db:migrate

$ rake -T
rake about                              # List versions of all Rails frameworks and the environment
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 db:create                          # Creates the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:create:all to create all databases in the config)
rake db:drop                            # Drops the database from DATABASE_URL or config/database.yml for the current RAILS_ENV (use db:drop:all to drop all databases in the config)
rake db:fixtures:load                   # Load fixtures into the current environment's database
rake db:migrate                         # Migrate the database (options: VERSION=x, VERBOSE=false, SCOPE=blog)
rake db:migrate:status                  # Display status of migrations
rake db:rollback                        # Rolls the schema back to the previous version (specify steps w/ STEP=n)
rake db:schema:cache:clear              # Clear a db/schema_cache.dump file
rake db:schema:cache:dump               # Create a db/schema_cache.dump file
rake db:schema:dump                     # Create a db/schema.rb file that is portable against any DB supported by AR
rake db:schema:load                     # Load a schema.rb file into the database
rake db:seed                            # Load the seed data from db/seeds.rb
rake db:setup                           # Create the database, load the schema, and initialize with the seed data (use db:reset to also drop the database first)
rake db:structure:dump                  # Dump the database structure to db/structure.sql
rake db:structure:load                  # Recreate the databases from the structure.sql file
rake db:version                         # Retrieves the current schema version number
rake doc:app                            # Generate docs for the app -- also available doc:rails, doc:guides (options: TEMPLATE=/rdoc-template.rb, TITLE="Custom Title")
rake log:clear                          # Truncates all *.log files in log/ to zero bytes (specify which logs with LOGS=test,development)

rails new
rails generate scaffold
rails generate controller
rails generate migration
rails generate model
rails server
rails destroy
rails plugin install
rails console
rails dbconsole
rails runner
rails about
rails assets
rails notes
rails routes
rails tmp

rails db:migrate
bin/rails db:migrate
bundle exec rails db:migrate