diff --git a/Gemfile b/Gemfile
index dde7f6d1f..f52a82458 100644
--- a/Gemfile
+++ b/Gemfile
@@ -54,7 +54,7 @@ end
 
 group :test do
   gem "database_cleaner", '1.6.2'
-  gem 'shoulda', ">= 3.5"
+  gem 'shoulda-matchers', '~> 3.1.2'
   gem 'fabrication'
   gem 'faker'
   gem 'capybara', '~> 2.7'
diff --git a/Gemfile.lock b/Gemfile.lock
index 6a7480ce9..57b021967 100644
--- a/Gemfile.lock
+++ b/Gemfile.lock
@@ -329,12 +329,8 @@ GEM
     selenium-webdriver (3.11.0)
       childprocess (~> 0.5)
       rubyzip (~> 1.2)
-    shoulda (3.5.0)
-      shoulda-context (~> 1.0, >= 1.0.1)
-      shoulda-matchers (>= 1.4.1, < 3.0)
-    shoulda-context (1.2.1)
-    shoulda-matchers (2.8.0)
-      activesupport (>= 3.0.0)
+    shoulda-matchers (3.1.2)
+      activesupport (>= 4.0.0)
     simple_form (3.1.0)
       actionpack (~> 4.0)
       activemodel (~> 4.0)
@@ -427,7 +423,7 @@ DEPENDENCIES
   rubocop (~> 0.52.1)
   sass-rails (~> 5.0.7)
   select2-rails
-  shoulda (>= 3.5)
+  shoulda-matchers (~> 3.1.2)
   simple_form (>= 3.0.0)
   skylight
   uglifier (= 2.7.2)
diff --git a/app/models/event.rb b/app/models/event.rb
new file mode 100644
index 000000000..2058045b7
--- /dev/null
+++ b/app/models/event.rb
@@ -0,0 +1,20 @@
+class Event < ActiveRecord::Base
+  enum action: { created: 0, updated: 1 }
+
+  belongs_to :post
+  belongs_to :member
+  belongs_to :transfer
+
+  validates :action, presence: true
+  validate :resource_presence
+
+  private
+
+  # Validates that only one resource id is set
+  #
+  def resource_presence
+    return if post_id.present? ^ member_id.present? ^ transfer_id.present?
+
+    errors.add(:base, 'Specify only one resource id: `post_id`, `member_id` or `transfer_id`')
+  end
+end
diff --git a/app/services/persister/member_persister.rb b/app/services/persister/member_persister.rb
index 4bed82cf1..51594ffd6 100644
--- a/app/services/persister/member_persister.rb
+++ b/app/services/persister/member_persister.rb
@@ -7,7 +7,33 @@ def initialize(member)
     end
 
     def save
-      member.save
+      ::ActiveRecord::Base.transaction do
+        member.save!
+        create_save_event!
+        member
+      end
+    rescue ActiveRecord::RecordInvalid => _exception
+      false
+    end
+
+    def update_attributes(params)
+      ::ActiveRecord::Base.transaction do
+        member.update_attributes!(params)
+        create_update_event!
+        member
+      end
+    rescue ActiveRecord::RecordInvalid => _exception
+      false
+    end
+
+    private
+
+    def create_save_event!
+      ::Event.create! action: :created, member: member
+    end
+
+    def create_update_event!
+      ::Event.create! action: :updated, member: member
     end
   end
 end
diff --git a/app/services/persister/post_persister.rb b/app/services/persister/post_persister.rb
index eb4e94fe3..0c0bb8004 100644
--- a/app/services/persister/post_persister.rb
+++ b/app/services/persister/post_persister.rb
@@ -7,11 +7,33 @@ def initialize(post)
     end
 
     def save
-      post.save
+      ::ActiveRecord::Base.transaction do
+        post.save!
+        create_save_event!
+        post
+      end
+    rescue ActiveRecord::RecordInvalid => _exception
+      false
     end
 
     def update_attributes(params)
-      post.update_attributes(params)
+      ::ActiveRecord::Base.transaction do
+        post.update_attributes!(params)
+        create_update_event!
+        post
+      end
+    rescue ActiveRecord::RecordInvalid => _exception
+      false
+    end
+
+    private
+
+    def create_save_event!
+      ::Event.create! action: :created, post: post
+    end
+
+    def create_update_event!
+      ::Event.create! action: :updated, post: post
     end
   end
 end
diff --git a/app/services/persister/transfer_persister.rb b/app/services/persister/transfer_persister.rb
index 5e72e46d7..a5fd86f12 100644
--- a/app/services/persister/transfer_persister.rb
+++ b/app/services/persister/transfer_persister.rb
@@ -7,7 +7,33 @@ def initialize(transfer)
     end
 
     def save
-      transfer.save
+      ::ActiveRecord::Base.transaction do
+        transfer.save!
+        create_save_event!
+        transfer
+      end
+    rescue ActiveRecord::RecordInvalid => _exception
+      false
+    end
+
+    def update_attributes(params)
+      ::ActiveRecord::Base.transaction do
+        transfer.update_attributes!(params)
+        create_update_event!
+        transfer
+      end
+    rescue ActiveRecord::RecordInvalid => _exception
+      false
+    end
+
+    private
+
+    def create_save_event!
+      ::Event.create! action: :created, transfer: transfer
+    end
+
+    def create_update_event!
+      ::Event.create! action: :updated, transfer: transfer
     end
   end
 end
diff --git a/db/migrate/20180501093846_create_events.rb b/db/migrate/20180501093846_create_events.rb
new file mode 100644
index 000000000..af3fffbee
--- /dev/null
+++ b/db/migrate/20180501093846_create_events.rb
@@ -0,0 +1,43 @@
+# This migration does not use Rails ActiveRecord ORM DSL since
+# it doesn't provide data integrity (foreign key) for polymorphic models.
+#
+# The technique applied is called Exclusive Belongs To (AKA Exclusive Arc)
+#
+# Please read the following article for more details:
+# https://hashrocket.com/blog/posts/modeling-polymorphic-associations-in-a-relational-database
+#
+class CreateEvents < ActiveRecord::Migration
+  def up
+    create_table :events do |t|
+      t.integer :action, null:false
+      t.integer :post_id
+      t.integer :member_id
+      t.integer :transfer_id
+      t.timestamps
+    end
+
+    add_foreign_key :events, :posts, name: 'events_post_id_fkey'
+    add_foreign_key :events, :members, name: 'events_member_id_fkey'
+    add_foreign_key :events, :transfers, name: 'events_transfer_id_fkey'
+
+    add_index :events, :post_id, unique: true, where: 'post_id IS NOT NULL'
+    add_index :events, :member_id, unique: true, where: 'member_id IS NOT NULL'
+    add_index :events, :transfer_id, unique: true, where: 'transfer_id IS NOT NULL'
+
+    execute <<-SQL
+      ALTER TABLE events
+        ADD CHECK(action IN (0, 1)),
+        ADD CHECK(
+          (
+            (post_id IS NOT NULL)::integer +
+            (member_id IS NOT NULL)::integer +
+            (transfer_id IS NOT NULL)::integer
+          ) = 1
+        );
+    SQL
+  end
+
+  def down
+    drop_table :events
+  end
+end
diff --git a/db/schema.rb b/db/schema.rb
index e4e2e2e1d..f3751e936 100644
--- a/db/schema.rb
+++ b/db/schema.rb
@@ -11,7 +11,7 @@
 #
 # It's strongly recommended that you check this file into your version control system.
 
-ActiveRecord::Schema.define(version: 20180221161343) do
+ActiveRecord::Schema.define(version: 20180501093846) do
 
   # These are extensions that must be enabled in order to support this database
   enable_extension "plpgsql"
@@ -76,6 +76,19 @@
   add_index "documents", ["documentable_id", "documentable_type"], name: "index_documents_on_documentable_id_and_documentable_type", using: :btree
   add_index "documents", ["label"], name: "index_documents_on_label", using: :btree
 
+  create_table "events", force: :cascade do |t|
+    t.integer  "action",      null: false
+    t.integer  "post_id"
+    t.integer  "member_id"
+    t.integer  "transfer_id"
+    t.datetime "created_at"
+    t.datetime "updated_at"
+  end
+
+  add_index "events", ["member_id"], name: "index_events_on_member_id", unique: true, where: "(member_id IS NOT NULL)", using: :btree
+  add_index "events", ["post_id"], name: "index_events_on_post_id", unique: true, where: "(post_id IS NOT NULL)", using: :btree
+  add_index "events", ["transfer_id"], name: "index_events_on_transfer_id", unique: true, where: "(transfer_id IS NOT NULL)", using: :btree
+
   create_table "members", force: :cascade do |t|
     t.integer  "user_id"
     t.integer  "organization_id"
@@ -198,4 +211,7 @@
   add_index "users", ["email"], name: "index_users_on_email", using: :btree
 
   add_foreign_key "accounts", "organizations"
+  add_foreign_key "events", "members", name: "events_member_id_fkey"
+  add_foreign_key "events", "posts", name: "events_post_id_fkey"
+  add_foreign_key "events", "transfers", name: "events_transfer_id_fkey"
 end
diff --git a/spec/fabricators/transfer_fabricator.rb b/spec/fabricators/transfer_fabricator.rb
new file mode 100644
index 000000000..02b6c193a
--- /dev/null
+++ b/spec/fabricators/transfer_fabricator.rb
@@ -0,0 +1,5 @@
+Fabricator(:transfer) do
+  source { Fabricate(:account) }
+  destination { Fabricate(:account) }
+  amount 10
+end
diff --git a/spec/models/event_spec.rb b/spec/models/event_spec.rb
new file mode 100644
index 000000000..2961fc2ee
--- /dev/null
+++ b/spec/models/event_spec.rb
@@ -0,0 +1,49 @@
+require 'spec_helper'
+
+describe Event do
+  describe 'Validations' do
+    it { is_expected.to validate_presence_of(:action) }
+    it do
+      is_expected.to define_enum_for(:action)
+        .with([:created, :updated])
+    end
+
+    describe '#resource_presence validation' do
+      let(:post) { Fabricate(:post) }
+      let(:member) { Fabricate(:member) }
+      let(:event) { Event.new action: 'created' }
+
+      context 'has no resources' do
+        it { expect(event).to_not be_valid }
+      end
+
+      context 'has one resource' do
+        before { event.post = post }
+
+        it { expect(event).to be_valid }
+      end
+
+      context 'has two resources' do
+        before { event.post = post; event.member = member }
+
+        it { expect(event).to_not be_valid }
+      end
+    end
+  end
+
+  describe 'Relations' do
+    it { is_expected.to belong_to(:post) }
+    it { is_expected.to belong_to(:member) }
+    it { is_expected.to belong_to(:transfer) }
+
+    it { is_expected.to have_db_column(:post_id) }
+    it { is_expected.to have_db_column(:member_id) }
+    it { is_expected.to have_db_column(:transfer_id) }
+  end
+
+  describe 'Indexes' do
+    it { is_expected.to have_db_index(:post_id) }
+    it { is_expected.to have_db_index(:member_id) }
+    it { is_expected.to have_db_index(:transfer_id) }
+  end
+end
diff --git a/spec/services/persister/member_persister_spec.rb b/spec/services/persister/member_persister_spec.rb
index 9ca7f61b6..7377ee375 100644
--- a/spec/services/persister/member_persister_spec.rb
+++ b/spec/services/persister/member_persister_spec.rb
@@ -3,15 +3,32 @@
 describe Persister::MemberPersister do
   let(:organization) { Fabricate(:organization) }
   let(:user) { Fabricate(:user) }
+  let(:member) { Fabricate.build(:member, user: user, organization: organization) }
+  let(:persister) { ::Persister::MemberPersister.new(member) }
 
   describe '#save' do
+    before { persister.save }
+
     it 'saves the member' do
-      member = Member.new(user: user, organization: organization)
+      expect(member).to be_persisted
+    end
 
-      persister = ::Persister::MemberPersister.new(member)
-      persister.save
+    # TODO: write better expectation
+    it 'creates an event' do
+      expect(Event.where(member_id: member.id).first.action).to eq('created')
+    end
+  end
 
-      expect(member).to be_persisted
+  describe '#update_attributes' do
+    before { persister.update_attributes(member_uid: 666) }
+
+    it 'updates the resource attributes' do
+      expect(member.member_uid).to eq(666)
+    end
+
+    # TODO: write better expectation
+    it 'creates an event' do
+      expect(Event.where(member_id: member.id).first.action).to eq('updated')
     end
   end
 end
diff --git a/spec/services/persister/post_persister_spec.rb b/spec/services/persister/post_persister_spec.rb
index 9592b1fd2..6ae8139b6 100644
--- a/spec/services/persister/post_persister_spec.rb
+++ b/spec/services/persister/post_persister_spec.rb
@@ -4,25 +4,40 @@
   let(:organization) { Fabricate(:organization) }
   let(:user) { Fabricate(:user) }
   let(:category) { Fabricate(:category) }
-  let(:post) { Fabricate(:post, organization: organization) }
+  let(:post) do
+    Fabricate.build(
+      :offer,
+      organization: organization,
+      user: user,
+      category: category,
+      title: 'Title'
+    )
+  end
+  let(:persister) { ::Persister::PostPersister.new(post) }
 
   describe '#save' do
-    it 'saves the post' do
-      post = Offer.new(organization: organization, user: user, category: category, title: 'Title')
-      persister = ::Persister::PostPersister.new(post)
-
-      persister.save
+    before { persister.save }
 
+    it 'saves the post' do
       expect(post).to be_persisted
     end
+
+    # TODO: write better expectation
+    it 'creates an event' do
+      expect(Event.where(post_id: post.id).first.action).to eq('created')
+    end
   end
 
   describe '#update_attributes' do
-    it 'updates the attributes' do
-      persister = ::Persister::PostPersister.new(post)
-      persister.update_attributes(title: 'New title')
+    before { persister.update_attributes(title: 'New title') }
 
+    it 'updates the resource attributes' do
       expect(post.title).to eq('New title')
     end
+
+    # TODO: write better expectation
+    it 'creates an event' do
+      expect(Event.where(post_id: post.id).first.action).to eq('updated')
+    end
   end
 end
diff --git a/spec/services/persister/transfer_persister_spec.rb b/spec/services/persister/transfer_persister_spec.rb
index a7d77dab8..89acc338b 100644
--- a/spec/services/persister/transfer_persister_spec.rb
+++ b/spec/services/persister/transfer_persister_spec.rb
@@ -5,15 +5,39 @@
   let(:destination_account) { Fabricate(:account) }
   let(:organization) { Fabricate(:organization) }
   let(:post) { Fabricate(:post, organization: organization) }
+  let(:transfer) do
+    Fabricate.build(
+      :transfer,
+      post: post,
+      source: source_account,
+      destination: destination_account
+    )
+  end
+  let(:persister) { ::Persister::TransferPersister.new(transfer) }
 
   describe '#save' do
+    before { persister.save }
+
     it 'saves the transfer' do
-      transfer = Transfer.new(post: post, source: source_account, destination: destination_account)
+      expect(transfer).to be_persisted
+    end
+
+    # TODO: write better expectation
+    it 'creates an event' do
+      expect(Event.where(transfer_id: transfer.id).first.action).to eq('created')
+    end
+  end
 
-      persister = ::Persister::TransferPersister.new(transfer)
-      persister.save
+  describe '#update_attributes' do
+    before { persister.update_attributes(amount: 666) }
 
-      expect(transfer).to be_persisted
+    it 'updates the resource attributes' do
+      expect(transfer.amount).to eq(666)
+    end
+
+    # TODO: write better expectation
+    it 'creates an event' do
+      expect(Event.where(transfer_id: transfer.id).first.action).to eq('updated')
     end
   end
 end
diff --git a/spec/spec_helper.rb b/spec/spec_helper.rb
index 43434d797..8e737cd26 100644
--- a/spec/spec_helper.rb
+++ b/spec/spec_helper.rb
@@ -10,6 +10,7 @@
 require 'fabrication'
 require 'selenium/webdriver'
 require 'faker'
+require 'shoulda/matchers'
 I18n.reload!
 
 Capybara.register_driver :chrome do |app|
@@ -149,3 +150,10 @@ def set_browser_locale(locale)
 end
 
 RSpec.configure(&:infer_spec_type_from_file_location!)
+
+Shoulda::Matchers.configure do |config|
+  config.integrate do |with|
+    with.test_framework :rspec
+    with.library :rails
+  end
+end