title: Cannot change colors of lines in ggplot
body: <p>I have created the following plot using ggplot2:
  <a href="https://i.stack.imgur.com/JVzta.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/JVzta.png" alt="enter image description here"></a></p>
  
  <p>Now I want the blue line to be a red dashed line and I want the red line to be a black line. I have used the following code to produce the plot:</p>
  
  <pre><code>ggplot(data=SLLN, aes(x=X1, y=X2, group=1)) + 
    geom_line(aes(colour = "Variable name A")) +                    
    geom_hline(aes(yintercept=theor_price, colour = "Variable name B")) +
    geom_point(size=1) +                       
    scale_x_log10(breaks = trans_breaks("log10", function(x) 10^x), #make log scale
    labels = trans_format("log10", math_format(10^.x))) +
    ylim(175, 250) +                           
    scale_colour_hue(name="", l=30)  +                  
    (lightness=30)
    scale_shape_manual(values=c(22,21)) +     
    scale_linetype_discrete() +
    xlab("xlab") + ylab("ylab") + 
    ggtitle("Title name") +     
    theme_bw()+
    theme(legend.background = element_rect(fill="transparent"), 
    legend.position=c(.85, .7)) 
  </code></pre>
  
  <p>When I remove aes() in geom_line and geom_hline, and change the argument of color to "black" and "red", the lines have the color I want, but they dissappear from the legend? How can I keep the image as it is now, so with the legend, and only change the colors of the lines and make the horizontal line dashed?</p>
  
  <p>Thank you in advance!</p>