Add ability to render readme templates

- This pretty much mimics the way that Thor, or more appropriately,
Rails generators renders templates.

app/services/projects/create_service.rb

@@ -3,6 +3,7 @@
 module Projects
   class CreateService < BaseService
     include ValidatesClassificationLabel
+    TEMPLATE_PATH = Rails.root.join('app', 'services', 'projects', 'create_service', 'templates')
 
     def initialize(user, params)
       @current_user = user
@@ -151,12 +152,16 @@ module Projects
         branch_name: @default_branch.presence || @project.default_branch_or_main,
         commit_message: 'Initial commit',
         file_path: 'README.md',
-        file_content: "# #{@project.name}\n\n#{@project.description}"
+        file_content: template('readme_basic.md')
       }
 
       Files::CreateService.new(@project, current_user, commit_attrs).execute
     end
 
+    def template(name)
+      ERB.new(File.read(TEMPLATE_PATH.join("#{name}.tt")), trim_mode: '<>').result(binding)
+    end
+
     def skip_wiki?
       !@project.feature_available?(:wiki, current_user) || @skip_wiki
     end

app/services/projects/create_service/templates/readme_basic.md.tt

+# <%= @project.name %>
+
+<%= @project.description %>