fix failing assets:precompile step

Deploying fails on the `assets:precompile` step with:
```
Uglifier::Error:  (Uglifier::Error)
/uglifier.rb:291:in `parse_result'
```

Issue here: lautis/uglifier#185

There's a workaround suggested in the issue, but it's also suggested to move to the [Terser gem](https://github.com/ahorek/terser-ruby) as Uglifier's last update was more than 5 years ago, and Terser's is 3 weeks ago.

This moves to the Terser gem.

Gemfile

@@ -167,3 +167,5 @@ gem 'browser', "~> 4.2"
 gem "rack-utf8_sanitizer", "~> 1.7"
 
 # gem "tailwindcss-rails", "~> 2.0"
+
+gem "terser", "~> 1.2"

Gemfile.lock

@@ -501,6 +501,8 @@ GEM
       net-sftp (>= 2.1.2)
       net-ssh (>= 2.8.0)
     stringio (3.1.0)
+    terser (1.2.2)
+      execjs (>= 0.3.0, < 3)
     thor (1.3.1)
     tilt (2.3.0)
     timeout (0.4.1)
@@ -602,6 +604,7 @@ DEPENDENCIES
   sprockets-rails
   sqlite3 (~> 1.4)
   starburst!
+  terser (~> 1.2)
   turbolinks (~> 5.2)
   twitter-bootstrap-rails!
   twitter-typeahead-rails!

config/environments/production.rb

@@ -21,10 +21,11 @@
   # config.require_master_key = true
 
   # Disable serving static files from `public/`, relying on NGINX/Apache to do so instead.
-  # config.public_file_server.enabled = false
+  config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
   # Compress JS assets. Needed for Sprockets
-  config.assets.js_compressor = Uglifier.new(harmony: true)
+  # config.assets.js_compressor = Uglifier.new(harmony: true)
+  config.assets.js_compressor = :terser
 
   # Compress CSS using a preprocessor.
   # config.assets.css_compressor = :sass

config/environments/remotedev.rb

@@ -19,7 +19,8 @@
   config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
   # Compress JavaScripts and CSS.
-  config.assets.js_compressor = Uglifier.new(harmony: true)
+  config.assets.js_compressor = :terser
+
   # config.assets.css_compressor = :sass
 
   # Do not fallback to assets pipeline if a precompiled asset is missed.
@@ -71,7 +72,7 @@
   config.active_support.deprecation = :notify
 
   # Use default logging formatter so that PID and timestamp are not suppressed.
-  config.log_formatter = ::Logger::Formatter.new
+  config.log_formatter = Logger::Formatter.new
 
   # Use a different logger for distributed setups.
   # require 'syslog/logger'

config/environments/staging.rb

@@ -19,7 +19,8 @@
   config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
 
   # Compress JavaScripts and CSS.
-  config.assets.js_compressor = Uglifier.new(harmony: true)
+  config.assets.js_compressor = :terser
+
   # config.assets.css_compressor = :sass
 
   # Do not fallback to assets pipeline if a precompiled asset is missed.
@@ -71,7 +72,7 @@
   config.active_support.deprecation = :notify
 
   # Use default logging formatter so that PID and timestamp are not suppressed.
-  config.log_formatter = ::Logger::Formatter.new
+  config.log_formatter = Logger::Formatter.new
 
   # Use a different logger for distributed setups.
   # require 'syslog/logger'