Merge pull request scikit-learn#5042 from amueller/contributing_addition

[MRG] DOC: adding algorithms is not the best way to contribute

Author: amueller

doc/developers/contributing.rst

@@ -9,14 +9,18 @@ contribute.
 
 The project is hosted on http://github.com/scikit-learn/scikit-learn
 
+Scikit-learn is somewhat :ref:`selective <selectiveness>` when it comes to
+adding new algorithms, and the best way to contribute and to help the project
+is to start working on known issues.
+See :ref:`easy_issues` to get started.
 
 Submitting a bug report
 =======================
 
 In case you experience issues using this package, do not hesitate to submit a
 ticket to the
 `Bug Tracker <http://github.com/scikit-learn/scikit-learn/issues>`_. You are
-also welcome to post feature requests or links to pull requests.
+also welcome to post feature requests or pull requests.
 
 
 .. _git_repo:
@@ -203,6 +207,8 @@ and Cython optimizations.
    <http://astropy.readthedocs.org/en/latest/development/workflow/development_workflow.html>`_
    sections.
 
+.. _easy_issues:
+
 Easy Issues
 -----------
 

doc/faq.rst

@@ -22,7 +22,9 @@ Apart from scikit-learn, another popular one is `scikit-image <http://scikit-ima
 
 How can I contribute to scikit-learn?
 -----------------------------------------
-See :ref:`contributing`.
+See :ref:`contributing`. Before wanting to add a new algorithm, which is
+usually a major and lengthy undertaking, it is recommended to start with :ref:`known
+issues <easy_issues>`.
 
 Can I add this new algorithm that I (or someone else) just published?
 -------------------------------------------------------------------------