Merge branch 'update_license_api_docs' into 'master'

Update license API docs [ci skip]

Docs for gitlab-org/gitlab-ee!400

I forgot the docs in the above merge request so here they are. This adds the new `POST /license` endpoint. 

See merge request !413

doc/api/license.md

 # License
 
-## Retrieve information about the current license
-
-In order to retrieve the license information, you need to authenticate yourself
+In order to interact with license endpoints, you need to authenticate yourself
 as an admin.
 
+## Retrieve information about the current license
+
 ```
 GET /license
 ```
@@ -22,3 +22,36 @@ GET /license
   "active_users": 60
 }
 ```
+
+## Add a new license
+
+```
+POST /license
+```
+
+| Attribute | Type | Required | Description |
+| --------- | ---- | -------- | ----------- |
+| `license` | string | yes | The license string |
+
+```bash
+curl -X POST -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" "https://gitlab.example.com/api/v3/license?license=eyJkYXRhIjoiMHM5Q...S01Udz09XG4ifQ=="
+```
+
+Example response:
+
+```json
+{
+  "starts_at": "2015-10-24",
+  "expires_at": "2016-10-24",
+  "licensee": {
+    "Name": "John Doe",
+    "Company": "Doe, Inc.",
+    "Email": "john@doe.com"
+  },
+  "user_limit": 100,
+  "active_users": 60
+}
+```
+
+It returns `201` if it succeeds or `400` if failed with an error message
+explaining the reason.

doc/api/license_templates.md

+# License Templates
+
+## List license templates
+
+Get all license templates.
+
+```
+GET /licenses
+```
+
+| Attribute | Type    | Required | Description           |
+| --------- | ------- | -------- | --------------------- |
+| `popular` | boolean | no       | If passed, returns only popular licenses |
+
+```bash
+curl https://gitlab.example.com/api/v3/licenses?popular=1
+```
+
+Example response:
+
+```json
+[
+    {
+        "key": "apache-2.0",
+        "name": "Apache License 2.0",
+        "nickname": null,
+        "featured": true,
+        "html_url": "http://choosealicense.com/licenses/apache-2.0/",
+        "source_url": "http://www.apache.org/licenses/LICENSE-2.0.html",
+        "description": "A permissive license that also provides an express grant of patent rights from contributors to users.",
+        "conditions": [
+            "include-copyright",
+            "document-changes"
+        ],
+        "permissions": [
+            "commercial-use",
+            "modifications",
+            "distribution",
+            "patent-use",
+            "private-use"
+        ],
+        "limitations": [
+            "trademark-use",
+            "no-liability"
+        ],
+        "content": "                                 Apache License\n                           Version 2.0, January 2004\n [...]"
+    },
+    {
+        "key": "gpl-3.0",
+        "name": "GNU General Public License v3.0",
+        "nickname": "GNU GPLv3",
+        "featured": true,
+        "html_url": "http://choosealicense.com/licenses/gpl-3.0/",
+        "source_url": "http://www.gnu.org/licenses/gpl-3.0.txt",
+        "description": "The GNU GPL is the most widely used free software license and has a strong copyleft requirement. When distributing derived works, the source code of the work must be made available under the same license.",
+        "conditions": [
+            "include-copyright",
+            "document-changes",
+            "disclose-source",
+            "same-license"
+        ],
+        "permissions": [
+            "commercial-use",
+            "modifications",
+            "distribution",
+            "patent-use",
+            "private-use"
+        ],
+        "limitations": [
+            "no-liability"
+        ],
+        "content": "                    GNU GENERAL PUBLIC LICENSE\n                       Version 3, 29 June 2007\n [...]"
+    },
+    {
+        "key": "mit",
+        "name": "MIT License",
+        "nickname": null,
+        "featured": true,
+        "html_url": "http://choosealicense.com/licenses/mit/",
+        "source_url": "http://opensource.org/licenses/MIT",
+        "description": "A permissive license that is short and to the point. It lets people do anything with your code with proper attribution and without warranty.",
+        "conditions": [
+            "include-copyright"
+        ],
+        "permissions": [
+            "commercial-use",
+            "modifications",
+            "distribution",
+            "private-use"
+        ],
+        "limitations": [
+            "no-liability"
+        ],
+        "content": "The MIT License (MIT)\n\nCopyright (c) [year] [fullname]\n [...]"
+    }
+]
+```
+
+## Single license template
+
+Get a single license template. You can pass parameters to replace the license
+placeholder.
+
+```
+GET /licenses/:key
+```
+
+| Attribute  | Type   | Required | Description |
+| ---------- | ------ | -------- | ----------- |
+| `key`      | string | yes      | The key of the license template |
+| `project`  | string | no       | The copyrighted project name |
+| `fullname` | string | no       | The full-name of the copyright holder |
+
+>**Note:**
+If you omit the `fullname` parameter but authenticate your request, the name of
+the authenticated user will be used to replace the copyright holder placeholder.
+
+```bash
+curl -H "PRIVATE-TOKEN: 9koXpg98eAheJpvBs5tK" https://gitlab.example.com/api/v3/licenses/mit?project=My+Cool+Project
+```
+
+Example response:
+
+```json
+{
+    "key": "mit",
+    "name": "MIT License",
+    "nickname": null,
+    "featured": true,
+    "html_url": "http://choosealicense.com/licenses/mit/",
+    "source_url": "http://opensource.org/licenses/MIT",
+    "description": "A permissive license that is short and to the point. It lets people do anything with your code with proper attribution and without warranty.",
+    "conditions": [
+        "include-copyright"
+    ],
+    "permissions": [
+        "commercial-use",
+        "modifications",
+        "distribution",
+        "private-use"
+    ],
+    "limitations": [
+        "no-liability"
+    ],
+    "content": "The MIT License (MIT)\n\nCopyright (c) 2016 John Doe\n [...]"
+}
+```