title: .where vs find. ActiveRecord::Relation NoMethodError
body: <p>I'm new to rails and this might seem obvious, but couldn't find a answer.</p>
  
  <p>when i do </p>
  
  <pre><code>u = User.where("email=?", email_string)
  u.name = "new name" 
  </code></pre>
  
  <p>doesn't work i keep getting</p>
  
  <pre><code>NoMethodError: undefined method `name=' for #&lt;ActiveRecord::Relation:0x1049c2890&gt; 
  </code></pre>
  
  <p>but if i change </p>
  
  <pre><code>u = User.where("email=?", email_string)
  </code></pre>
  
  <p><strong>to</strong> </p>
  
  <pre><code>u = User.find_by_email(email_string)
  </code></pre>
  
  <p>i can see my changes being persisted and no error thrown. </p>
  
  <p>So what am i missing. is it that <strong>.where</strong> returns a read only object or something ? </p>