Add gem paper_trail

3 files changed, 42 insertions, 0 deletions

diff --git a/Gemfile b/Gemfile
index 88fd635ea..3c625a530 100644
--- a/Gemfile
+++ b/Gemfile
@@ -33,6 +33,9 @@ gem 'spring', group: :development
 # ActiveRecord associations on top of PostgreSQL arrays
 gem 'has_array_of', af83: 'has_array_of'
 
+# Track changes to your models' data. Good for auditing or versioning.
+gem 'paper_trail'
+
 gem 'rails-observers'
 
 # Use SeedBank for spliting seeds
diff --git a/Gemfile.lock b/Gemfile.lock
index 9262eeb74..f9682dff1 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -321,6 +321,10 @@ GEM
       mini_portile2 (~> 2.3.0)
     open4 (1.3.4)
     orm_adapter (0.5.0)
+    paper_trail (4.1.0)
+      activerecord (>= 3.0, < 6.0)
+      activesupport (>= 3.0, < 6.0)
+      request_store (~> 1.1)
     parser (2.4.0.0)
       ast (~> 2.2)
     pg (0.20.0)
@@ -621,6 +625,7 @@ DEPENDENCIES
   map_layers (= 0.0.4)
   mimemagic
   newrelic_rpm
+  paper_trail
   pg
   phantomjs
   poltergeist
diff --git a/db/migrate/20171121142536_create_versions.rb b/db/migrate/20171121142536_create_versions.rb
new file mode 100644
index 000000000..ff794f9e1
--- /dev/null
+++ b/db/migrate/20171121142536_create_versions.rb
@@ -0,0 +1,34 @@
+class CreateVersions < ActiveRecord::Migration
+
+  # The largest text column available in all supported RDBMS is
+  # 1024^3 - 1 bytes, roughly one gibibyte.  We specify a size
+  # so that MySQL will use `longtext` instead of `text`.  Otherwise,
+  # when serializing very large objects, `text` might not be big enough.
+  TEXT_BYTES = 1_073_741_823
+
+  def change
+    create_table :versions do |t|
+      t.string   :item_type, :null => false
+      t.integer  :item_id,   :null => false
+      t.string   :event,     :null => false
+      t.string   :whodunnit
+      t.text     :object,    :limit => TEXT_BYTES
+
+      # Known issue in MySQL: fractional second precision
+      # -------------------------------------------------
+      #
+      # MySQL timestamp columns do not support fractional seconds unless
+      # defined with "fractional seconds precision". MySQL users should manually
+      # add fractional seconds precision to this migration, specifically, to
+      # the `created_at` column.
+      # (https://dev.mysql.com/doc/refman/5.6/en/fractional-seconds.html)
+      #
+      # MySQL users should also upgrade to rails 4.2, which is the first
+      # version of ActiveRecord with support for fractional seconds in MySQL.
+      # (https://github.com/rails/rails/pull/14359)
+      #
+      t.datetime :created_at
+    end
+    add_index :versions, [:item_type, :item_id]
+  end
+end