Add method for coverage badge in badges controller

app/controllers/projects/badges_controller.rb

@@ -4,11 +4,24 @@ class Projects::BadgesController < Projects::ApplicationController
   before_action :no_cache_headers, except: [:index]
 
   def build
-    badge = Gitlab::Badge::Build::Status.new(project, params[:ref])
+    build_status = Gitlab::Badge::Build::Status
+      .new(project, params[:ref])
 
+    render_badge build_status
+  end
+
+  def coverage
+    coverage_report = Gitlab::Badge::Coverage::Report
+      .new(project, params[:ref], params[:job])
+
+    render_badge coverage_report
+  end
+
+  private
+
+  def render_badge(badge)
     respond_to do |format|
       format.html { render_404 }
-
       format.svg do
         render 'badge', locals: { badge: badge.template }
       end