title: How to grab all data from dataframe column into a dictionary?
body: <p>Lets say I have a dataframe like this:</p>
  <pre><code>     first|second|
  1      a  |   123|
  2      b  |   234|
  3      a  |    23|
  4      b  |     1|
  5      c  |    53|
  6      a  |    32|
  </code></pre>
  <p>and I'd like to have a dict like this:
  dict = {'a': [123, 23, 32], 'b':[234, 1], 'c':[53]}</p>
  <p>I have thought to use groupby but couldn't figure out how.
  I know it should be a for loop somehow:
  add every element from the first column as keys
  add every element from the second column to the keys they match.</p>