title: R plotly orca Error: No mapbox access token found
body: <p>I read tutorial <a href="https://github.com/plotly/orca#installation" rel="nofollow noreferrer">https://github.com/plotly/orca#installation</a> and run commands in docker image:</p>
  
  <pre><code>apt-get install -y curl &amp;&amp; \
  curl -sL https://deb.nodesource.com/setup_8.x | sudo -E bash - &amp;&amp; \
  apt-get install -y nodejs libgconf-2-4 libgtk2.0-0 &amp;&amp; \
  npm install -g electron@1.8.4 orca --unsafe-perm=true --allow-root
  </code></pre>
  
  <p>OS details:</p>
  
  <pre><code>root@8a17254aeb9a:/# lsb_release -a
  No LSB modules are available.
  Distributor ID: Debian
  Description:    Debian GNU/Linux 9.6 (stretch)
  Release:    9.6
  Codename:   stretch
  </code></pre>
  
  <p>but nothing happens when I execute:</p>
  
  <pre><code>root@8a17254aeb9a:/# which orca
  /usr/bin/orca
  root@8a17254aeb9a:/# orca
  root@8a17254aeb9a:/# orca --help
  root@8a17254aeb9a:/# electron
  root@8a17254aeb9a:/# electron -v
  </code></pre>
  
  <p>and when I execute example R code I get error:</p>
  
  <pre><code>&gt; library(plotly)
  &gt; p &lt;- plot_ly(z = ~volcano) %&gt;% add_surface()
  &gt; orca(p, "surface-plot.svg")
  Error: No mapbox access token found. Obtain a token here
  https://www.mapbox.com/help/create-api-access-token/
  Once you have a token, assign it to an environment variable 
  named 'MAPBOX_TOKEN', for example,
  Sys.setenv('MAPBOX_TOKEN' = 'secret token')
  </code></pre>
  
  <p>I read a lot of tutorials and issues, but still have no answer. Can you help?</p>