class Projects::GroupLinksController < Projects::ApplicationController
  layout 'project_settings'
  before_action :authorize_admin_project!

  def index
    @group_links = project.project_group_links.all
  end

  def create
    group = Group.find(params[:link_group_id])

    if can?(current_user, :read_group, group)
      link = project.project_group_links.new
      link.group_id = params[:link_group_id]
      link.group_access = params[:link_group_access]
      link.save
    else
      return render_404
    end

    redirect_to namespace_project_group_links_path(project.namespace, project)
  end

  def destroy
    project.project_group_links.find(params[:id]).destroy

    redirect_to namespace_project_group_links_path(project.namespace, project)
  end
end

class Projects::GroupLinksController < Projects::ApplicationController
  layout 'project_settings'
  before_action :authorize_admin_project!

  def index
    @group_links = project.project_group_links.all
  end

  def create
    group = Group.find(params[:link_group_id])

    if can?(current_user, :read_group, group)
      project.project_group_links.create(
        group: group, group_access: params[:link_group_access]
      )
    else
      return render_404
    end

    redirect_to namespace_project_group_links_path(project.namespace, project)
  end

  def destroy
    project.project_group_links.find(params[:id]).destroy

    redirect_to namespace_project_group_links_path(project.namespace, project)
  end
end

Refactor method that shares project with a group
Refactor method that shares project with a group
