Added a new articule about using/installing inestable Symfony versions

Author: javiereguiluz

cookbook/index.rst

@@ -17,6 +17,7 @@ The Cookbook
     email/index
     event_dispatcher/index
     form/index
+    install/index
     logging/index
     profiler/index
     request/index

cookbook/install/index.rst

@@ -0,0 +1,7 @@
+Install and Upgrade
+===================
+
+.. toctree::
+    :maxdepth: 2
+
+    upgrading

cookbook/install/inestable_versions

@@ -0,0 +1,95 @@
+How to Install and Use an Inestable Symfony Version
+===================================================
+
+Symfony releases two new minor versions (2.5, 2.6, 2.7, etc.) per year, one in
+May and one in November (:doc:`see releases detail <contributing/community/releases>`).
+Testing the new Symfony versions in your projects as soon as possible is important
+to ensure that they will keep working as expected.
+
+In this article you'll learn how to install and use new Symfony versions before
+they are released as stable versions.
+
+Creating a New Project Based on an Inestable Symfony Version
+------------------------------------------------------------
+
+Suppose that Symfony 2.7 version hasn't been released yet and you want to create
+a new project to test its features. First, :doc:`install Composer </cookbook/composer>`
+package manager. Then, open a command console, enter your projects directory and
+execute the following command:
+
+.. code-block:: bash
+
+    $ composer create-project symfony/framework-standard-edition my_project "2.7.*" --stability=dev
+
+Once the command finishes its execution, you'll have a new Symfony project created
+in the ``my_project/`` directory and based on the most recent code found in the
+``2.7`` branch.
+
+If you want to test a beta version, use ``beta`` as the value of the ``stability``
+option:
+
+.. code-block:: bash
+
+    $ composer create-project symfony/framework-standard-edition my_project "2.7.*" --stability=beta
+
+Upgrading your Project to an Inestable Symfony Version
+------------------------------------------------------
+
+Instead of creating a new empty project, in this section you'll update an existing
+Symfony application to an inestable framework version. Suppose again that Symfony
+2.7 version hasn't been released yet and you want to test it in your project.
+
+First, open the ``composer.json`` file located in the root directory of your
+project. Then, edit the value of the version defined for the ``symfony/symfony``
+dependency:
+
+.. code-block:: json
+
+    {
+        "require": {
+            // ...
+            "symfony/symfony" : "2.7.*"
+        }
+    }
+
+Then, before updating your dependencies, make sure that the project configuration
+allows to install inestable versions. If the ``composer.json`` file contains a
+``minimum-stability`` option, change its value to ``dev``. If that option doesn't
+exist, add it as follows:
+
+.. code-block:: json
+
+    {
+        "require": {
+            // ...
+            "symfony/symfony" : "2.7.*"
+        },
+        "minimum-stability": "dev"
+    }
+
+If you prefer to test a Symfony beta version, replace the ``dev`` value of the
+``minimum-stability`` option by ``beta``.
+
+Then, open a command console, enter your project directory and execute the following command to update your project dependencies:
+
+.. code-block:: bash
+
+    $ composer update
+
+.. tip::
+
+    If you use Git to manage the project's code, it's a good practice to create
+    a new branch to test the new Symfony version. This solution avoids introducing
+    any issue in your application and allows you to test the new version with
+    total confidence:
+
+    .. code-block:: bash
+
+        $ cd projects/my_project/
+        $ git checkout -b testing_new_symfony
+        // update composer.json configuration
+        $ composer update
+
+        // ... after testing the new Symfony version
+        $ git checkout master
+        $ git branch -D testing_new_symfony

cookbook/upgrading.rst renamed to cookbook/install/upgrading.rst

@@ -107,6 +107,11 @@
   * (validation) :doc:`/cookbook/validation/custom_constraint`
   * (doctrine) :doc:`/cookbook/doctrine/file_uploads`
 
+* **Installing and Upgrading**
+
+  * :doc:`/cookbook/upgrading`
+  * :doc:`/cookbook/inestable_version`
+
 * :doc:`/cookbook/logging/index`
 
   * :doc:`/cookbook/logging/monolog`
@@ -201,10 +206,6 @@
   * (email) :doc:`/cookbook/email/testing`
   * (form) :doc:`/cookbook/form/unit_testing`
 
-* **Upgrading**
-
-  * :doc:`/cookbook/upgrading`
-
 * :doc:`/cookbook/validation/index`
 
   * :doc:`/cookbook/validation/custom_constraint`