title: Match data between dataframes columns and then paste the data avaliable on one of them
body: <p>I know that the title could be a Little confussing, but basically this is what I want.</p>
  <p>Lets supposse I have a a dataframe of this form</p>
  <pre><code>P_SEXO P_EDADR COD_ENCUESTAS
     &lt;dbl&gt;   &lt;dbl&gt;         &lt;dbl&gt;
  1      2      16            74
  2      2       9            75
  3      2      18            75
  4      2      11            75
  5      2      11            76
  6      2       1            76
  </code></pre>
  <p>As you can see, theres some values that repeats on <code>COD_ENCUESTAS</code>, this is because its like an índex in another dataframe (df2).</p>
  <p>Df2 have a form like this:</p>
  <pre><code>COD_ENCUESTAS VA1_ESTRATO
            &lt;dbl&gt;       &lt;dbl&gt;
  1           74          24
  2           75          23
  3           76          12
  4           77           23
  5           78           14
  6           79          11
  </code></pre>
  <p>I want output:</p>
  <pre><code>P_SEXO P_EDADR COD_ENCUESTAS    VA1_ESTRTO 
     &lt;dbl&gt;   &lt;dbl&gt;         &lt;dbl&gt;   &lt;dbl&gt;
  1      2      16            74    24
  2      2       9            75    23
  3      2      18            75    23
  4      2      11            75    23
  5      2      11            76    12
  6      2       1            76    12
  </code></pre>
  <p>Thnaks beforehand
  -lasagna</p>