Initialize projects with readme through API

Add a `initialize_with_readme` parameter to POST /projects.

EE port of https://gitlab.com/gitlab-org/gitlab-ce/merge_requests/21617

changelogs/unreleased/21617-initialize-projects-with-readme.yml

+---
+title: Adds a initialize_with_readme parameter to POST /projects
+merge_request: 21617
+author: Steve
+type: added

doc/api/projects.md

@@ -666,6 +666,7 @@ POST /projects
 | `avatar`    | mixed   | no      | Image file for avatar of the project                |
 | `printing_merge_request_link_enabled` | boolean | no | Show link to create/view merge request when pushing from the command line |
 | `ci_config_path` | string | no | The path to CI config file |
+| `initialize_with_readme` | boolean | no | `false` by default |
 | `repository_storage` | string | no | Which storage shard the repository is on. Available only to admins |
 | `approvals_before_merge` | integer | no | How many approvers should approve merge request by default |
 | `mirror` | boolean | no | Enables pull mirroring in a project |

lib/api/helpers/projects_helpers.rb

@@ -26,6 +26,7 @@ module API
             optional :avatar, type: File, desc: 'Avatar image for project'
             optional :printing_merge_request_link_enabled, type: Boolean, desc: 'Show link to create/view merge request when pushing from the command line'
             optional :merge_method, type: String, values: %w(ff rebase_merge merge), desc: 'The merge method used when merging merge requests'
+            optional :initialize_with_readme, type: Boolean, desc: "Initialize a project with a README.md"
           end
 
           params :optional_project_params_ee do

spec/requests/api/projects_spec.rb

@@ -557,6 +557,14 @@ describe API::Projects do
       expect(json_response['visibility']).to eq('private')
     end
 
+    it 'creates a new project initialized with a README.md' do
+      project = attributes_for(:project, initialize_with_readme: 1, name: 'somewhere')
+
+      post api('/projects', user), project
+
+      expect(json_response['readme_url']).to eql("#{Gitlab.config.gitlab.url}/#{json_response['namespace']['full_path']}/somewhere/blob/master/README.md")
+    end
+
     it 'sets tag list to a project' do
       project = attributes_for(:project, tag_list: %w[tagFirst tagSecond])