Use strong_migrations gem

Gemfile

@@ -58,12 +58,12 @@ gem "sentry-raven"
 gem "shoryuken", "3.1.11"
 gem "sqlite3", platforms: [:ruby, :mswin, :mingw, :mswin, :x64_mingw]
 gem "stringex", require: false
+# catch problematic migrations at development/test time
+gem "strong_migrations"
 # execjs runtime
 gem "therubyracer", platforms: :ruby
 # Use Uglifier as compressor for JavaScript assets
 gem "uglifier", ">= 1.3.0"
-# catch problematic migrations at development/test time
-gem "zero_downtime_migrations"
 
 group :production, :staging, :ssh_forwarding, :development, :test do
   # Oracle DB

Gemfile.lock

@@ -464,6 +464,8 @@ GEM
       sprockets (>= 3.0.0)
     sqlite3 (1.3.13)
     stringex (2.8.5)
+    strong_migrations (0.3.1)
+      activerecord (>= 3.2.0)
     terminal-table (1.8.0)
       unicode-display_width (~> 1.1, >= 1.1.1)
     therubyracer (0.12.3)
@@ -496,8 +498,6 @@ GEM
       nokogiri (~> 1.5)
     xpath (3.0.0)
       nokogiri (~> 1.8)
-    zero_downtime_migrations (0.0.7)
-      activerecord
 
 PLATFORMS
   ruby
@@ -567,11 +567,11 @@ DEPENDENCIES
   sniffybara!
   sqlite3
   stringex
+  strong_migrations
   therubyracer
   timecop
   tzinfo-data
   uglifier (>= 1.3.0)
-  zero_downtime_migrations
 
 BUNDLED WITH
    1.17.2

Rakefile

@@ -7,3 +7,5 @@ require File.expand_path("config/application", __dir__)
 Dir[Rails.root.join("lib/tasks/support/**/*.rb")].each { |f| require f }
 
 Rails.application.load_tasks
+
+task "db:schema:dump": "strong_migrations:alphabetize_columns"

config/initializers/strong_migrations.rb

@@ -0,0 +1 @@
+StrongMigrations.start_after = 20190111000717

db/migrate/20190110220936_make_hearing_views_polymorphic.rb

@@ -1,13 +1,13 @@
 class MakeHearingViewsPolymorphic < ActiveRecord::Migration[5.1]
-  safety_assured
-
   def change
-    add_column :hearing_views, :hearing_type, :string
-    remove_index :hearing_views, [:hearing_id, :user_id]
-    add_index :hearing_views, [:hearing_id, :user_id, :hearing_type], unique: true
+    safety_assured do
+      add_column :hearing_views, :hearing_type, :string
+      remove_index :hearing_views, [:hearing_id, :user_id]
+      add_index :hearing_views, [:hearing_id, :user_id, :hearing_type], unique: true
 
-    HearingView.find_each do |hearing_view|
-      hearing_view.update!(hearing_type: "LegacyHearing")
+      HearingView.find_each do |hearing_view|
+        hearing_view.update!(hearing_type: "LegacyHearing")
+      end
     end
   end
 end