Draft: Implement BranchRules::CreateApprovalProjectRuleService

What does this MR do and why?

Implement BranchRules::CreateApprovalProjectRuleService

This service takes name approvals_required user_ids group_ids and creates a regular ApprovalProjectRule for the branch rule.

• Regular branch rules will create an approval rule for the branch rule's protected_branch.
• All branches rules will create an approval rule with no protected_branch with applies_to_all_protected_branches: false. -All protected branches rules will create an approval rule with no protected_branch with applies_to_all_protected_branches: true.

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Before	After

How to set up and validate locally

You'll need to be a member of the Flightjs/flight project, if you are not then add yourself to that project first or use a project that you are a member of.

1. Open the graphql explorer http://gdk.test:3000/-/graphql-explorer
2. Create a branch rule

mutation {
  branchRuleCreate(input: { name: "test", projectPath: "Flightjs/flight" }) {
    errors
    branchRule {
      id
    }
  }
}

3. Alternatively find the global ID of an existing branch rule using the project query (if this fails you can also create a protected branch through the project settings > repository > protected branches

query {
  project(fullPath: "Flightjs/flight") {
    branchRules {
      nodes {
        id
        name
      }
    }
  }
}

4. Open a rails console

bin/rails console
current_user = User.find_by_username("your_username")
branch_rule = GlobalID::Locator.locate(id) # id from the branch rule you created in step 2 or found in step 3
project = branch_rule.project
user_ids = project.users.without_bots.ids
group_ids = [project.group.id]
params = { name: 'test rule', approvals_required: 2, user_ids: user_ids, group_ids: group_ids }
response = BranchRules::CreateApprovalProjectRuleService.new(branch_rule, current_user, params).execute
# Tests
response.success? # should be true
approval_project_rule = response[:approval_project_rule] # should be the created rule
response[:errors] # should be nil
approval_project_rule.name == params[:name]
approval_project_rule.required_approvals == params[:required_approvals]
approval_project_rule.user_ids.difference(user_ids).none?
approval_project_rule.group_ids.difference(group_ids).none?
branch_rule.approval_project_rules.include?(approval_project_rule)