title: Can't create model on ruby on rails
body: <p>I'm starting to learn ruby on rails. the problem that i have is that i don't know why i get there while i want to create model 
  this is the command that  i tried
   rails generate model Book</p>
  
  <p>and get this error in my ubuntu 16 terminal</p>
  
  <pre><code>/home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/app_loader.rb:40: warning: Insecure world writable dir /opt in PATH, mode 040777
  /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/application/configuration.rb:148:in `rescue in database_configuration': YAML syntax error occurred while parsing /home/android/ruby Tutorial/library/config/database.yml. Please note that YAML must be consistently indented using spaces. Tabs are not allowed. Error: (&lt;unknown&gt;): found a tab character that violate intendation while scanning a plain scalar at line 17 column 10 (RuntimeError)
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/application/configuration.rb:131:in `database_configuration'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.1/lib/active_record/railtie.rb:122:in `block (2 levels) in &lt;class:Railtie&gt;'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/lazy_load_hooks.rb:43:in `instance_eval'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/lazy_load_hooks.rb:43:in `execute_hook'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/lazy_load_hooks.rb:50:in `block in run_load_hooks'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/lazy_load_hooks.rb:49:in `each'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/lazy_load_hooks.rb:49:in `run_load_hooks'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.1/lib/active_record/base.rb:324:in `&lt;module:ActiveRecord&gt;'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activerecord-5.0.1/lib/active_record/base.rb:24:in `&lt;top (required)&gt;'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:293:in `require'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:293:in `block in require'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:259:in `load_dependency'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/activesupport-5.0.1/lib/active_support/dependencies.rb:293:in `require'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:345:in `active_record_configured?'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:263:in `disconnect_database'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:97:in `preload'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:143:in `serve'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:131:in `block in run'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:125:in `loop'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application.rb:125:in `run'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/spring-2.0.0/lib/spring/application/boot.rb:19:in `&lt;top (required)&gt;'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from /home/android/.rbenv/versions/2.3.3/lib/ruby/2.3.0/rubygems/core_ext/kernel_require.rb:55:in `require'
      from -e:1:in `&lt;main&gt;'
  </code></pre>
  
  <p>i also tried this</p>
  
  <pre><code>rails script/generate model Book
  </code></pre>
  
  <p>and i get this error:</p>
  
  <pre><code>/home/android/.rbenv/versions/2.3.3/lib/ruby/gems/2.3.0/gems/railties-5.0.1/lib/rails/app_loader.rb:40: warning: Insecure world writable dir /opt in PATH, mode 040777
  rails aborted!
  Don't know how to build task 'script/generate' (see --tasks)
  /home/android/ruby Tutorial/library/bin/rails:9:in `require'
  /home/android/ruby Tutorial/library/bin/rails:9:in `&lt;top (required)&gt;'
  /home/android/ruby Tutorial/library/bin/spring:14:in `&lt;top (required)&gt;'
  bin/rails:3:in `load'
  bin/rails:3:in `&lt;main&gt;'
  (See full trace by running task with --trace)
  </code></pre>
  
  <p>//Edit</p>
  
  <p>I check my database but and also check yamlint website also has error on line 17 but there is no error</p>
  
  <pre><code># SQLite version 3.x
  #   gem install sqlite3
  #
  #   Ensure the SQLite 3 gem is defined in your Gemfile
  #   gem 'sqlite3'
  #
  default: &amp;default
    adapter: mysql
    pool: 5
    timeout: 5000
  
  development:
     adapter: mysql
     database: library_development
     username: root
     password: root1234
     host: localhost
  
  test:
     adapter: mysql
     database: library_test
     username: root
     password: root1234
     host: localhost
  
  production:
     adapter: mysql
     database: library_production
     username: root
     password: root1234
     host: localhost
  </code></pre>