title: Set UTF-8 as default for Ruby 1.9.3
body: <p>I'm on Rails 4 and Ruby 1.9.3</p>
  
  <p>I use "strange" characters very often, so I have to declare UTF-8 encoding at the top of all .rb files.</p>
  
  <p>Is there any way to set UTF-8 as the default encoding for Ruby 1.9.3?</p>
  
  <hr>
  
  <p>I tried all answers, but when running <code>rake db:seed</code> and creating an object whose attributes contain non <code>US-ASCII</code> valid characters, I still receive this error:</p>
  
  <pre><code>`block in trace_on': invalid byte sequence in US-ASCII (ArgumentError)
  </code></pre>