title: Colorscales using Plots.jl
body: <p>I'm having some troubles trying to chance the colorgradient of a heat map using Plots. The documentation lacks of an example in the section Color (<a href="https://juliaplots.github.io/colors/" rel="nofollow noreferrer">https://juliaplots.github.io/colors/</a>). I think that the default color gradient is <code>:inferno</code> but I don't like it. Does someone know a complete list of standard gradients or a way to make my own color gradient?</p>
  
  <pre><code>x_range = linspace(0, 2, 100)
  y_range = linspace(0,2, 100)
  z = rand(100, 100)
  heatmap(x_range, y_range, z, color = :blues)
  </code></pre>