终端报错

$rails g controller welcome

/Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/railties-5.0.0/lib/rails/application/configuration.rb:143:in `database_configuration': Cannot load `Rails.application.database_configuration`:

Could not load database configuration. No such file - ["config/database.yml"] (RuntimeError)

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activerecord-5.0.0/lib/active_record/railtie.rb:122:in `block (2 levels) in '

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/lazy_load_hooks.rb:38:in `instance_eval'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/lazy_load_hooks.rb:38:in `execute_hook'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/lazy_load_hooks.rb:45:in `block in run_load_hooks'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/lazy_load_hooks.rb:44:in `each'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/lazy_load_hooks.rb:44:in `run_load_hooks'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activerecord-5.0.0/lib/active_record/base.rb:324:in `'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activerecord-5.0.0/lib/active_record/base.rb:24:in `'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:293:in `require'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:293:in `block in require'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:259:in `load_dependency'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/activesupport-5.0.0/lib/active_support/dependencies.rb:293:in `require'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:338:in `active_record_configured?'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:259:in `disconnect_database'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:97:in `preload'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:143:in `serve'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:131:in `block in run'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:125:in `loop'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application.rb:125:in `run'

from /Users/lvchengbo/.rvm/gems/ruby-2.3.1/gems/spring-1.7.2/lib/spring/application/boot.rb:19:in `'

from /Users/lvchengbo/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'

from /Users/lvchengbo/.rvm/rubies/ruby-2.3.1/lib/ruby/site_ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'

from -e:1:in `<main>`

解决办法

运行命令，生成文件 config/database.yml

touch config/database.yml

贴进去

# SQLite version 3.x
#   gem install sqlite3
#
#   Ensure the SQLite 3 gem is defined in your Gemfile
#   gem 'sqlite3'
#
default: &default
  adapter: sqlite3
  pool: 5
  timeout: 5000

development:
  <<: *default
  database: db/development.sqlite3

# Warning: The database defined as "test" will be erased and
# re-generated from your development database when you run "rake".
# Do not set this db to the same as development or production.
test:
  <<: *default
  database: db/test.sqlite3

production:
  <<: *default
  database: db/production.sqlite3