Install chromium for prod + extend process timeout

Dockerfile

@@ -16,7 +16,7 @@ WORKDIR /rails
 
 # Install base packages
 RUN apt-get update -qq && \
-    apt-get install --no-install-recommends -y curl libjemalloc2 libvips sqlite3 && \
+    apt-get install --no-install-recommends -y curl libjemalloc2 libvips sqlite3 chromium && \
     rm -rf /var/lib/apt/lists /var/cache/apt/archives
 
 # Set production environment

app/controllers/contestants_controller.rb

@@ -131,6 +131,10 @@ class ContestantsController < ApplicationController
     @contestants = @contest.contestants.sort_by { |contestant| contestant.name }
     @nonav = true
 
+    FerrumPdf.configure do |config|
+      config.process_timeout = 20
+    end
+
     respond_to do |format|
       format.html
       format.pdf { render ferrum_pdf: {}, disposition: :inline, filename: "#{@contest.friendly_id}_qrcodes.pdf", layout: "blank" }