Add Sentry to Rails

Now we're tracking both JS and Rails errors, phew!

Gemfile

@@ -71,3 +71,7 @@ gem 'bootsnap', '~> 1.16', require: false
 gem "rack-mini-profiler", "~> 3.1"
 gem "memory_profiler", "~> 1.0"
 gem "stackprof", "~> 0.2.25"
+
+# For monitoring errors in production.
+gem "sentry-ruby", "~> 5.12"
+gem "sentry-rails", "~> 5.12"

Gemfile.lock

@@ -269,6 +269,11 @@ GEM
       sprockets (> 3.0)
       sprockets-rails
       tilt
+    sentry-rails (5.12.0)
+      railties (>= 5.0)
+      sentry-ruby (~> 5.12.0)
+    sentry-ruby (5.12.0)
+      concurrent-ruby (~> 1.0, >= 1.0.2)
     sprockets (4.2.0)
       concurrent-ruby (~> 1.0)
       rack (>= 2.2.4, < 4)
@@ -334,6 +339,8 @@ DEPENDENCIES
   rest-client (~> 2.1)
   sanitize (~> 6.0, >= 6.0.2)
   sass-rails (~> 6.0)
+  sentry-rails (~> 5.12)
+  sentry-ruby (~> 5.12)
   sprockets (~> 4.2)
   stackprof (~> 0.2.25)
   terser (~> 1.1, >= 1.1.17)

config/initializers/sentry.rb

@@ -0,0 +1,5 @@
+Sentry.init do |config|
+  config.dsn = 'https://cb4b3f56c1ec50ba0667b189617446bb@o506079.ingest.sentry.io/4506180803559424'
+  config.breadcrumbs_logger = [:active_support_logger, :http_logger]
+  config.traces_sample_rate = 0.2
+end