Track which projects a user contributed to.

Closes #43460.

app/models/event.rb

@@ -65,6 +65,7 @@ class Event < ActiveRecord::Base
   # Callbacks
   after_create :reset_project_activity
   after_create :set_last_repository_updated_at, if: :push?
+  after_create :track_user_contributed_projects
 
   # Scopes
   scope :recent, -> { reorder(id: :desc) }
@@ -389,4 +390,8 @@ class Event < ActiveRecord::Base
     Project.unscoped.where(id: project_id)
       .update_all(last_repository_updated_at: created_at)
   end
+
+  def track_user_contributed_projects
+    UserContributedProjects.track(self)
+  end
 end

app/models/user_contributed_projects.rb

@@ -0,0 +1,13 @@
+class UserContributedProjects < ActiveRecord::Base
+  belongs_to :user
+  belongs_to :project
+
+  validates :project, presence: true
+  validates :user, presence: true
+
+  def self.track(event)
+    find_or_create_by!(project: event.project, user: event.author)
+  rescue ActiveRecord::RecordNotUnique
+    retry
+  end
+end

spec/models/event_spec.rb

@@ -49,6 +49,14 @@ describe Event do
         end
       end
     end
+
+    describe 'after_create :track_user_contributed_projects' do
+      it 'passes event to UserContributedProjects.track' do
+        event = build(:push_event, project: project, author: project.owner)
+        expect(UserContributedProjects).to receive(:track).with(event)
+        event.save
+      end
+    end
   end
 
   describe "Push event" do

spec/models/user_contributed_projects_spec.rb

@@ -0,0 +1,37 @@
+require 'spec_helper'
+
+describe UserContributedProjects do
+
+  describe '.track' do
+    subject { described_class.track(event) }
+    let(:event) { build(:event) }
+
+    Event::ACTIONS.each do |action|
+      context "for all actions (event types)" do
+        let(:event) { build(:event, action: action) }
+        it 'creates a record' do
+          expect { subject }.to change { UserContributedProjects.count }.from(0).to(1)
+        end
+
+      end
+    end
+
+    it 'sets project accordingly' do
+      expect(subject.project).to eq(event.project)
+    end
+
+    it 'sets user accordingly' do
+      expect(subject.user).to eq(event.author)
+    end
+
+    it 'only creates a record once per user/project' do
+      expect do
+        subject
+        described_class.track(event)
+      end.to change { UserContributedProjects.count }.from(0).to(1)
+    end
+  end
+
+  it { is_expected.to validate_presence_of(:project) }
+  it { is_expected.to validate_presence_of(:user) }
+end