Improve MR seeds

Signed-off-by: Dmitriy Zaporozhets <dmitriy.zaporozhets@gmail.com>

db/fixtures/development/10_merge_requests.rb

 Gitlab::Seeder.quiet do
-  (1..100).each  do |i|
-    # Random Project
-    project = Project.all.sample
-
-    # Random user
-    user = project.team.users.sample
-
-    next unless user
-
-    next if project.empty_repo?
-
-    branches = project.repository.branch_names.sample(2)
-
-    next if branches.uniq.size < 2
-
-    user_id = user.id
-
-    Gitlab::Seeder.by_user(user) do
-      MergeRequest.seed(:id, [{
-        id: i,
-        source_branch: branches.first,
-        target_branch: branches.last,
-        source_project_id: project.id,
-        target_project_id: project.id,
-        author_id: user_id,
-        assignee_id: user_id,
-        milestone: project.milestones.sample,
-        title: Faker::Lorem.sentence(6)
-      }])
+  Project.all.reject(&:empty_repo?).each do |project|
+    branches = project.repository.branch_names
+
+    branches.each do |branch_name|
+      break if branches.size < 2
+      source_branch = branches.pop
+      target_branch = branches.pop
+
+      # Random user
+      user = project.team.users.sample
+      next unless user
+
+      params = {
+        source_branch: source_branch,
+        target_branch: target_branch,
+        title: Faker::Lorem.sentence(6),
+        description: Faker::Lorem.sentences(3).join(" ")
+      }
+
+      merge_request = MergeRequests::CreateService.new(project, user, params).execute
+
+      if merge_request.valid?
+        merge_request.assignee = user
+        merge_request.milestone = project.milestones.sample
+        merge_request.save
+        print '.'
+      else
+        print 'F'
+      end
     end
-    print('.')
   end
 end
-
-MergeRequest.all.map do |mr|
-  mr.set_iid
-  mr.save
-end
-
-puts 'Load diffs for Merge Requests (it will take some time)...'
-MergeRequest.all.each do |mr|
-  mr.reload_code
-  print '.'
-end