diff --git a/app/models/contest.rb b/app/models/contest.rb
index c5480120..2277e9fc 100644
--- a/app/models/contest.rb
+++ b/app/models/contest.rb
@@ -18,7 +18,7 @@ class Contest < ActiveRecord::Base
   scope :practicable, -> { where(:practicable => true) }
   scope :visible, -> { where(:visible => true) }
 
-  validates_presence_of :name, :duration, :start_time
+  validates_presence_of :name, :duration, :start_time, :end_time
   validates_numericality_of :duration
 
   validates_inclusion_of :runner_type, :in => RUNNER_TYPES
diff --git a/app/models/problem.rb b/app/models/problem.rb
index b29e762f..b1f7db65 100644
--- a/app/models/problem.rb
+++ b/app/models/problem.rb
@@ -8,6 +8,8 @@ class Problem < ActiveRecord::Base
   has_and_belongs_to_many :categories
   has_one :problem_stats, dependent: :destroy
 
+  has_many_attached :assets
+
   validates_presence_of :name, :time_limit
   validates_numericality_of :time_limit, :memory_limit, :greater_than => 0
 
diff --git a/app/services/upload_problem_assets.rb b/app/services/upload_problem_assets.rb
new file mode 100644
index 00000000..e9d01c26
--- /dev/null
+++ b/app/services/upload_problem_assets.rb
@@ -0,0 +1,13 @@
+class UploadProblemAssets
+  def initialize(problem)
+    @problem = problem
+  end
+
+  def call
+    @problem.all_files.each do |file|
+      next if @problem.assets_blobs.any? { |blob| blob.filename == File.basename(file) }
+
+      @problem.assets.attach(io: File.open(file), filename: File.basename(file))
+    end
+  end
+end
\ No newline at end of file
diff --git a/config/environments/development.rb b/config/environments/development.rb
index 3c8d8312..2b893b6c 100644
--- a/config/environments/development.rb
+++ b/config/environments/development.rb
@@ -38,5 +38,5 @@
   config.active_job.queue_adapter = :sidekiq
 
   # Active Storage config
-  config.active_storage.service = :local
+  config.active_storage.service = :minio
 end
diff --git a/config/storage.yml b/config/storage.yml
new file mode 100644
index 00000000..02996e6a
--- /dev/null
+++ b/config/storage.yml
@@ -0,0 +1,13 @@
+local:
+  service: Disk
+  root: <%= Rails.root.join("storage") %>
+
+test:
+  service: Disk
+  root: <%= Rails.root.join("tmp/storage") %>
+
+minio:
+  service: S3
+  bucket: "maycamp-files"
+  endpoint: http://minio:9000
+  force_path_style: true
diff --git a/db/seeds.rb b/db/seeds.rb
index 4b6877d6..a632d059 100644
--- a/db/seeds.rb
+++ b/db/seeds.rb
@@ -5,12 +5,36 @@
 #
 #   cities = City.create([{ :name => 'Chicago' }, { :name => 'Copenhagen' }])
 #   Mayor.create(:name => 'Daley', :city => cities.first)
-u = User.create(
-  :login => 'root', 
-  :name => "The admin", 
-  :email => "valentin.mihov@gmail.com",
-  :unencrypted_password => "123123",
-  :unencrypted_password_confirmation => "123123",
-  :role => User::ADMIN,
-  :city => "Sofia"
-)
+User
+  .create_with(
+    name: "The admin",
+    email: "valentin.mihov@gmail.com",
+    unencrypted_password: "123123",
+    unencrypted_password_confirmation: "123123",
+    role: User::ADMIN,
+    city: "Sofia")
+  .find_or_create_by!(
+    login: 'root'
+  )
+
+group = Group.find_or_create_by!(name: "Група Е")
+
+contest = Contest.create_with(
+  duration: 300,
+  group: group,
+  start_time: 1.year.ago,
+  end_time: 1.year.ago,
+  runner_type: "fork"
+).find_or_create_by!(name: "Пролетен турнир 2020")
+
+problem1 = Problem.create_with(
+  contest: contest,
+  time_limit: 1,
+  memory_limit: 128.megabytes
+).find_or_create_by!(name: "Задача 1")
+
+problem2 = Problem.create_with(
+  contest: contest,
+  time_limit: 1,
+  memory_limit: 128.megabytes
+).find_or_create_by!(name: "Задача 2")
\ No newline at end of file
diff --git a/docker-compose.yaml b/docker-compose.yaml
index 115255e9..e1a75c8d 100644
--- a/docker-compose.yaml
+++ b/docker-compose.yaml
@@ -17,6 +17,9 @@ services:
       - DATABASE_URL=mysql2://arena:arena@mysql:3306/arena?encoding=utf8&collation=utf8_general_ci
       - REDIS_PROVIDER=redis://redis:6379
       - MEMCACHE_URL=memcached:11211
+      - AWS_ACCESS_KEY=AKIAIOSFODNN7EXAMPLE
+      - AWS_SECRET_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+      - AWS_REGION=us-east-1
       - SECRET_KEY_BASE=123
       - SECRET_TOKEN=123
       - SIDEKIQ_USERNAME=arena
@@ -44,6 +47,9 @@ services:
       - RAILS_ENV=development
       - DATABASE_URL=mysql2://arena:arena@mysql:3306/arena?encoding=utf8&collation=utf8_general_ci
       - REDIS_PROVIDER=redis://redis:6379
+      - AWS_ACCESS_KEY=AKIAIOSFODNN7EXAMPLE
+      - AWS_SECRET_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+      - AWS_REGION=us-east-1
     tmpfs:
       - /app/tmp
   grader:
@@ -59,6 +65,9 @@ services:
       - RAILS_ENV=development
       - DATABASE_URL=mysql2://arena:arena@mysql:3306/arena?encoding=utf8&collation=utf8_general_ci
       - REDIS_PROVIDER=redis://redis:6379
+      - AWS_ACCESS_KEY=AKIAIOSFODNN7EXAMPLE
+      - AWS_SECRET_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+      - AWS_REGION=us-east-1
     volumes:
       - ./sets:/app/sets:ro
       - ./sandbox:/app/sandbox
@@ -67,6 +76,16 @@ services:
     image: redis:alpine
   memcached:
     image: memcached:alpine
+  minio:
+    image: minio/minio
+    environment:
+      - MINIO_ACCESS_KEY=AKIAIOSFODNN7EXAMPLE
+      - MINIO_SECRET_KEY=wJalrXUtnFEMI/K7MDENG/bPxRfiCYEXAMPLEKEY
+    ports:
+      - 9000:9000
+    command: "server /data"
+    volumes:
+      - ./sets:/data
   mysql:
     image: mariadb
     volumes:
diff --git a/spec/services/upload_problem_assets_spec.rb b/spec/services/upload_problem_assets_spec.rb
new file mode 100644
index 00000000..2d71f437
--- /dev/null
+++ b/spec/services/upload_problem_assets_spec.rb
@@ -0,0 +1,31 @@
+describe UploadProblemAssets do
+  let(:problem) { create(:problem) }
+  let(:file_zip) { fixture_file_upload(file_fixture("archive.zip")) }
+  let(:file_in) { fixture_file_upload(file_fixture("task_input.in00")) }
+
+  it "creates assets for all uploaded files" do
+    ProcessUploadedFile.new(file_zip, problem).extract
+
+    expect(problem.all_files.length).to be > 0
+
+    UploadProblemAssets.new(problem).call
+
+    expect(problem.assets.count).to eq(problem.all_files.count)
+
+    expect(problem.assets_blobs.map(&:filename).sort + ["test"]).to eq(problem.all_files.map { |file| File.basename(file) }.sort)
+  end
+
+  it "is idempotent" do
+    ProcessUploadedFile.new(file_in, problem).extract
+
+    expect(problem.all_files.length).to eq(1)
+
+    UploadProblemAssets.new(problem).call
+
+    expect(problem.assets.count).to eq(1)
+
+    UploadProblemAssets.new(problem).call
+
+    expect(problem.assets.reload.count).to eq(1)
+  end
+end
\ No newline at end of file