title: Fill value in all rows of dataframe based on value
body: <p>So I have a dataframe as follows</p>
  
  <pre><code>   name, car
      foo, bmw
      bar, audi
      baz, tesla
      foobaz, bmw
  </code></pre>
  
  <p>now I have another dictionary like</p>
  
  <pre><code>car_type = {'bmw': 'gas', 'audi': 'hybrid', 'tesla': 'electric'}
  </code></pre>
  
  <p>Now, i want to add a new column to dataframe like following</p>
  
  <pre><code>   name, car, type
      foo, bmw, gas
      bar, audi, hybric
      baz, tesla, electric
      foobaz, bmw, gas
  </code></pre>
  
  <p>How do i do this in pandas?</p>