title: Change legend title ggplot2
body: <p>i got a plot in R based on ggplot2. Unfortunately, I have not enough reputation here to upload the plot. Now, I want to change my legend title and the names of the labels for two lines.</p>
  
  <p>Thus, I added <code>scale_fill_continuous(name = "New Legend Title", labels=c("Control", "Treatment"))</code> to the code.</p>
  
  <pre><code>ggplot(data=descripintens, 
  aes(x=syear, y=workingintensity, group= treatment, colour=factor(treatment))) + 
  geom_line() +
  xlab("Year") +
  ylab("Working intensity") +
  scale_fill_continuous(name = "New Legend Title", labels=c("Control", "Treatment"))
  </code></pre>
  
  <p>This is what is suggested in stackoverflow and the ggplot2 cheat sheet. Nothing changes. Not even an error comes up. </p>
  
  <p>What is wrong with my code?</p>
  
  <p>Thank you!</p>
  
  <p>EDIT: The data I used for the plot is a table, which is based on this code: </p>
  
  <pre><code>descripintens&lt;-intensity141516 %&gt;% 
    group_by(syear, treatment) %&gt;%
    summarise(workingintensity=mean(intensity))
  </code></pre>
  
  <p>The table <code>descripintens</code> looks like this: </p>
  
  <pre><code>   syear Treatment workingintensity
  1  2014     0         96.2
  2  2014     1         98.4
  3  2015     0         101.00000
  4  2015     1         102.00000
  5  2016     0         105.9
  6  2016     1         106.2
  </code></pre>