feature #3777 added docs for the core team (fabpot)

This PR was submitted for the master branch but it was merged into the 2.3 branch instead (closes #3777).

Discussion
----------

added docs for the core team

| Q             | A
| ------------- | ---
| Doc fix?      | no
| New docs?     | n/a
| Applies to    | all
| Fixed tickets | n/a

The Symfony Core Team is back!

Commits
-------

d734600 added docs for the core team

contributing/code/core_team.rst

@@ -0,0 +1,149 @@
+Symfony Core Team
+=================
+
+This document states the rules that govern the Symfony Core group. These rules
+are effective upon publication of this document and all Symfony Core members
+must adhere to said rules and protocol.
+
+Core Organization
+-----------------
+
+Symfony Core members are divided into three groups. Each member can only belong
+to one group at a time. The privileges granted to a group are automatically
+granted to all higher priority groups.
+
+The Symfony Core groups, in descending order of priority, are as follows:
+
+1. **Project Leader**
+
+* Elects members in any other group;
+* Merges pull requests in all Symfony repositories.
+
+2. **Mergers**
+
+* Merge pull requests for the component or components on which they have been
+  granted privileges.
+
+3. **Deciders**
+
+* Decide to merge or reject a pull request.
+
+Active Core Members
+~~~~~~~~~~~~~~~~~~~
+
+.. role:: leader
+.. role:: merger
+.. role:: decider
+
+* **Project Leader**:
+
+  * **Fabien Potencier** (:leader:`fabpot`).
+
+* **Mergers**:
+
+  * **Bernhard Schussek** (:merger:`webmozart`) can merge into the Form_,
+    Validator_, Icu_, Intl_, Locale_, OptionsResolver_ and PropertyAccess_
+    components;
+
+  * **Tobias Schultze** (:merger:`Tobion`) can merge into the Routing_
+    component;
+
+  * **Romain Neutron** (:merger:`romainneutron`) can merge into the
+    Process_ component;
+
+  * **Nicolas Grekas** (:merger:`nicolas-grekas`) can merge into the Debug_
+    component.
+
+* **Deciders**:
+
+  * **Christophe Coevoet** (:decider:`stof`);
+  * **Jakub Zalas** (:decider:`jakzal`);
+  * **Jordi Boggiano** (:decider:`seldaek`);
+  * **Lukas Kahwe Smith** (:decider:`lsmith77`).
+
+Core Membership Application
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+At present, new Symfony Core membership applications are not accepted.
+
+Core Membership Revocation
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A Symfony Core membership can be revoked for any of the following reasons:
+
+* Refusal to follow the rules and policies stated in this document;
+* Lack of activity for the past six months;
+* Willful negligence or intent to harm the Symfony project;
+* Upon decision of the **Project Leader**.
+
+Should new Symfony Core memberships be accepted in the future, revoked
+members must wait at least 12 months before re-applying.
+
+Code Development Rules
+----------------------
+
+Symfony project development is based on pull requests proposed by any member
+of the Symfony community. Pull request acceptance or rejection is decided based
+on the votes cast by the Symfony Core members.
+
+Pull Request Voting Policy
+~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+* ``-1`` votes must always be justified by technical and objective reasons;
+
+* ``+1`` votes do not require justification, unless there is at least one
+  ``-1`` vote;
+
+* Core members can change their votes as many times as they desire
+  during the course of a pull request discussion;
+
+* Core members are not allowed to vote on their own pull requests.
+
+Pull Request Merging Policy
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+A pull request **can be merged** if:
+
+* Enough time was given for peer reviews (a few minutes for typos or minor
+  changes, at least 2 days for "regular" pull requests, and 4 days for pull
+  requests with "a significant impact");
+
+* It is a minor change [1]_, regardless of the number of votes;
+
+* At least the component's **Merger** or two other Core members voted ``+1``
+  and no Core member voted ``-1``.
+
+Pull Request Merging Process
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+All code must be committed to the repository through pull requests, except for
+minor changes [1]_ which can be committed directly to the repository.
+
+**Mergers** must always use the command-line ``gh`` tool provided by the
+**Project Leader** to merge the pull requests.
+
+Release Policy
+~~~~~~~~~~~~~~
+
+The **Project Leader** is also the release manager for every Symfony version.
+
+Symfony Core Rules and Protocol Amendments
+------------------------------------------
+
+The rules described in this document may be amended at anytime at the
+discretion of the **Project Leader**.
+
+
+.. [1] Minor changes comprise typos, DocBlock fixes, code standards
+       violations, and minor CSS, JavaScript and HTML modifications.
+
+.. _Form: https://github.com/symfony/Form
+.. _Validator: https://github.com/symfony/Validator
+.. _Icu: https://github.com/symfony/Icu
+.. _Intl: https://github.com/symfony/Intl
+.. _Locale: https://github.com/symfony/Locale
+.. _OptionsResolver: https://github.com/symfony/OptionsResolver
+.. _PropertyAccess: https://github.com/symfony/PropertyAccess
+.. _Routing: https://github.com/symfony/Routing
+.. _Process: https://github.com/symfony/Process
+.. _Debug: https://github.com/symfony/Debug

contributing/code/index.rst

@@ -6,6 +6,7 @@ Contributing Code
 
     bugs
     patches
+    core_team
     security
     tests
     bc

contributing/map.rst.inc

@@ -2,6 +2,7 @@
 
   * :doc:`Bugs </contributing/code/bugs>`
   * :doc:`Patches </contributing/code/patches>`
+  * :doc:`The Core Team </contributing/code/core_team>`
   * :doc:`Security </contributing/code/security>`
   * :doc:`Tests </contributing/code/tests>`
   * :doc:`Backwards Compatibility </contributing/code/bc>`