Merge branch 'dev'

Dockerfile

README.md

package-lock.json

package.json

public/manifest.json

src/actions/auth.js

src/actions/groups.js

src/actions/homework.js

src/actions/mentors.js

src/actions/news.js

src/actions/statistics.js

src/actions/types.js

src/components/App.js

src/components/Footer.js

src/components/Header.js

src/components/Main.js

src/components/extra/GroupCard.js

src/components/forms/AddSolutionForm.js

src/components/forms/AddTaskForm.js

src/components/forms/ConfirmModal.js