Merge branch 'gokmengoksel/gitlab-ce-koding' into 'master'

Koding Integration

## What does this MR do?

Will provide Koding integration with GitLab services. Forked from !4914.

## Are there points in the code the reviewer needs to double check?
I've introduced new layouts which might not be necessary, first time contributor. 

## Why was this MR needed?
We're planning to ship Koding with GitLab.

## What are the relevant issue numbers?
#12759 #14698 

## Screenshots (if relevant)

### Screencasts

http://recordit.co/BDMbhwgxPD
http://recordit.co/By0qiz1ClC

### Enable Koding in Application Settings

![image](/uploads/73a69421105c03aa2b0b47e2617d3fbc/image.png)

### Koding Dashboard
![image](/uploads/6c7dda34792280c0e4791e36af4eba11/image.png)

### Set up Koding Stack
1 - ![image](/uploads/d5c2b93f8e61b5cbffdb06f0267d485f/image.png)
2 - ![image](/uploads/44d9a9b574b8ac0c5eb553fb9653d5da/image.png)

### Run on Koding on Project Page

![image](/uploads/7d2b46221009074ffff75d66d5a1a555/image.png)

### Run in IDE on Merge Requests
![image](/uploads/65eed90c34c34b5fe7ad29ef9c717640/image.png)

## Does this MR meet the acceptance criteria?

- [x] [CHANGELOG](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CHANGELOG) entry added
- [x] [Documentation created/updated](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/doc/development/doc_styleguide.md)
- [x] Tests
  - [x] Added for this feature/bug
  - [x] All builds are passing
- [x] Conform by the [style guides](https://gitlab.com/gitlab-org/gitlab-ce/blob/master/CONTRIBUTING.md#style-guides)
- [x] Branch has no merge conflicts with `master` (if you do - rebase it please)
- [x] [Squashed related commits together](https://git-scm.com/book/en/Git-Tools-Rewriting-History#Squashing-Commits)

See merge request !5909

2 files changed, 58 insertions, 0 deletions

diff --git a/app/helpers/application_settings_helper.rb b/app/helpers/application_settings_helper.rb
index 78c0b79d2bd..6de25bea654 100644
--- a/app/helpers/application_settings_helper.rb
+++ b/app/helpers/application_settings_helper.rb
@@ -31,6 +31,10 @@ module ApplicationSettingsHelper
     current_application_settings.akismet_enabled?
   end
 
+  def koding_enabled?
+    current_application_settings.koding_enabled?
+  end
+
   def allowed_protocols_present?
     current_application_settings.enabled_git_access_protocol.present?
   end
diff --git a/app/helpers/projects_helper.rb b/app/helpers/projects_helper.rb
index 505545fbabb..249d18c4486 100644
--- a/app/helpers/projects_helper.rb
+++ b/app/helpers/projects_helper.rb
@@ -236,6 +236,60 @@ module ProjectsHelper
     )
   end
 
+  def add_koding_stack_path(project)
+    namespace_project_new_blob_path(
+      project.namespace,
+      project,
+      project.default_branch || 'master',
+      file_name:      '.koding.yml',
+      commit_message: "Add Koding stack script",
+      content: <<-CONTENT.strip_heredoc
+        provider:
+          aws:
+            access_key: '${var.aws_access_key}'
+            secret_key: '${var.aws_secret_key}'
+        resource:
+          aws_instance:
+            #{project.path}-vm:
+              instance_type: t2.nano
+              user_data: |-
+
+                # Created by GitLab UI for :>
+
+                echo _KD_NOTIFY_@Installing Base packages...@
+
+                apt-get update -y
+                apt-get install git -y
+
+                echo _KD_NOTIFY_@Cloning #{project.name}...@
+
+                export KODING_USER=${var.koding_user_username}
+                export REPO_URL=#{root_url}${var.koding_queryString_repo}.git
+                export BRANCH=${var.koding_queryString_branch}
+
+                sudo -i -u $KODING_USER git clone $REPO_URL -b $BRANCH
+
+                echo _KD_NOTIFY_@#{project.name} cloned.@
+      CONTENT
+    )
+  end
+
+  def koding_project_url(project = nil, branch = nil, sha = nil)
+    if project
+      import_path = "/Home/Stacks/import"
+
+      repo = project.path_with_namespace
+      branch ||= project.default_branch
+      sha ||= project.commit.short_id
+
+      path = "#{import_path}?repo=#{repo}&branch=#{branch}&sha=#{sha}"
+
+      return URI.join(current_application_settings.koding_url, path).to_s
+    end
+
+    current_application_settings.koding_url
+  end
+
   def contribution_guide_path(project)
     if project && contribution_guide = project.repository.contribution_guide
       namespace_project_blob_path(