init project

app/services/projects/join_service.rb

@@ -0,0 +1,35 @@
+class Projects::JoinService < ApplicationService
+  attr_reader :project, :user, :opts
+
+  def initialize(project, user, **opts)
+    @project = project
+    @user    = user
+    @opts    = opts
+  end
+
+  def call
+    ActiveRecord::Base.transaction do
+      member = project.members.create!(user: user)
+
+      member.member_roles.create!(role_id: role_value)
+
+      project.user_grades.find_or_create_by!(user: user)
+    end
+
+    ApplyJoinProjectNotifyJob.perform_later(user, project, role_value)
+
+    project
+  end
+
+  private
+
+  def role_value
+    @_role ||=
+      case opts[:role]
+      when 'manager'   then 3
+      when 'developer' then 4
+      when 'reporter'  then 5
+      else raise ArgumentError
+      end
+  end
+end