switch to JS runtime to mini_racer (#3674)

the therubyracer is no longer maintained rubyjs/therubyracer#462

Gemfile

@@ -28,6 +28,7 @@ gem 'json-schema', '~> 2.8'
 gem 'librato-metrics', '~> 2.1.2'
 gem 'logstasher', '~> 1.3'
 gem 'mime-types'
+gem 'mini_racer'
 gem 'omniauth', '~> 1.9'
 gem 'omniauth-facebook', '~> 5.0'
 gem 'omniauth-google-oauth2'
@@ -50,7 +51,6 @@ gem 'sidetiq', '~> 0.7'
 gem 'standby'
 gem 'stringex', '~> 2.8'
 gem 'strong_migrations'
-gem 'therubyracer', '~> 0.12'
 gem 'uglifier', '~> 4.1'
 gem 'versionist', '~> 2.0'
 gem 'zoo_stream', '~> 1.0.1'

Gemfile.lock

@@ -207,7 +207,7 @@ GEM
     librato-metrics (2.1.2)
       aggregate (~> 0.2.2)
       faraday
-    libv8 (3.16.14.19)
+    libv8-node (15.14.0.1)
     listen (3.7.0)
       rb-fsevent (~> 0.10, >= 0.10.3)
       rb-inotify (~> 0.9, >= 0.9.10)
@@ -228,6 +228,8 @@ GEM
     mime-types-data (3.2020.0512)
     mini_mime (1.0.2)
     mini_portile2 (2.5.1)
+    mini_racer (0.4.0)
+      libv8-node (~> 15.14.0.0)
     minitest (5.14.4)
     mock_redis (0.25.0)
     modware (0.1.3)
@@ -326,7 +328,6 @@ GEM
     rb-inotify (0.10.1)
       ffi (~> 1.0)
     redis (4.2.1)
-    ref (2.0.0)
     regexp_parser (2.1.1)
     request_store (1.4.1)
       rack (>= 1.4)
@@ -428,9 +429,6 @@ GEM
     stringex (2.8.5)
     strong_migrations (0.3.1)
       activerecord (>= 3.2.0)
-    therubyracer (0.12.3)
-      libv8 (~> 3.16.14.15)
-      ref
     thor (0.20.3)
     thread_safe (0.3.6)
     timers (4.1.2)
@@ -486,6 +484,7 @@ DEPENDENCIES
   listen (~> 3.7)
   logstasher (~> 1.3)
   mime-types
+  mini_racer
   mock_redis
   newrelic_rpm
   omniauth (~> 1.9)
@@ -521,7 +520,6 @@ DEPENDENCIES
   standby
   stringex (~> 2.8)
   strong_migrations
-  therubyracer (~> 0.12)
   uglifier (~> 4.1)
   versionist (~> 2.0)
   zoo_stream (~> 1.0.1)