Add authorship policy for paper and software archives (#13)

This document lays out the general rules for giving credit to contributors. 
Our main goal is to be clear about this upfront and provide an incentive 
for academics looking to get involved in the project.

.travis.yml

@@ -12,7 +12,7 @@ branches:
 env:
   global:
       - secure: "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"
-      - TRACKED_FILES="CONTRIBUTING.md MAINTENANCE.md CODE_OF_CONDUCT.md"
+      - TRACKED_FILES="CONTRIBUTING.md MAINTENANCE.md CODE_OF_CONDUCT.md AUTHORSHIP.md"
       - REPOSITORIES="verde harmonica pooch rockhound boule erizo"
 
 install:

AUTHORSHIP.md

@@ -0,0 +1,74 @@
+# Authorship guidelines for academic papers and software archives
+
+First of all, we are deeply thankful to everyone who has helped make Fatiando a
+Terra what it is today. Our goal for this document is to establish guidelines
+for giving credit to contributors for their work.
+To do so, we will attempt to define:
+
+- Fair and diverse ways of providing recognition for contributors' efforts.
+- Define _contributions_ in a broad way: writing code and/or documentation,
+  providing ideas, fostering the community, etc.
+
+The following are the ways in which individuals who have contributed will be
+recognized.
+
+> **Note**: These policies are not set in stone and may be changed to
+> accommodate the growth of the project or the preferences of the community.
+
+## The `AUTHORS.md` file
+
+Anyone who has contributed a pull request to the project is welcome to add
+themselves to the `AUTHORS.md` file. This file lives in the repository and is
+packaged with distributions. This is an optional process.
+
+## Changelog for each release
+
+Every time we make a release, everyone who has made a commit to the repository
+since the previous release will be mentioned in the changelog entry. If their
+full name is available on GitHub, we will use it. Otherwise, we will use the
+GitHub handle. This is a way of saying "Thank you".
+
+## Authorship on Zenodo archives of releases
+
+Anyone who has contributed to the repository (i.e., appears on `git log`) will
+be invited to be an author on the Zenodo archive of new releases.
+
+To be included as an author, you *must* add the following to the `AUTHORS.md`
+file of the repository:
+
+1. Full name
+2. Affiliation (if omitted, we will use "Unaffiliated")
+3. ORCID (optional)
+
+The order of authors will be defined by the number of commits to the repository
+(`git shortlog -sne`). The order can also be changed on a case-by-case basis.
+
+If you have contributed and do not wish to be included in Zenodo archives,
+there are a few options:
+
+1. Don't add yourself to `AUTHORS.md`
+2. Remove yourself from `AUTHORS.md`
+3. Indicate next to your name on `AUTHORS.md` that you do not wish to be
+   included with something like `(not included in Zenodo)`.
+
+## Scientific publications (papers)
+
+We aim to write academic papers for most of your software packages. Ideally, we
+will publish updated papers for major changes or large new components of the
+package.
+
+To be included as an author on the paper, you *must* satisfy the following
+criteria:
+
+1. Have made a contribution to the repository or significant non-coding
+   contributions.
+2. Add your full name, affiliation, and (optionally) ORCID to the paper. These
+   can be submitted on pull requests to the corresponding paper repository.
+3. Write and/or read and review the manuscript in a timely manner and provide
+   comments on the paper (even if it's just an "OK", but preferably more).
+
+The order of authors will be defined by the number of commits made since the
+previous major release that has an associated paper (`git shortlog
+vX.0.0...HEAD -sne`). The order of any author who hasn't made any commits will
+be decided by all authors. The order can also be changed on a case-by-case
+basis.

CONTRIBUTING.md

@@ -35,6 +35,7 @@ read it carefully.
 
 * [What Can I Do?](#what-can-i-do)
 * [How Can I Talk to You?](#how-can-i-talk-to-you)
+* [Getting credit for contributions](#getting-credit-for-contributions)
 * [Reporting a Bug](#reporting-a-bug)
 * [Editing the Documentation](#editing-the-documentation)
 * [Contributing Code](#contributing-code)
@@ -65,6 +66,16 @@ In addition, there is a [Slack chat room](http://contact.fatiando.org) for the
 Fatiando a Terra project where you can ask questions.
 
 
+## Getting credit for contributions
+
+We appreciate the effort that goes into making a contribution to our
+open-source projects. To say "thank you" and provide an extra incentive, we
+have established some criteria for giving credit to contributors in different
+ways: from having your name in the changelog, to authorship on academic
+publications. Please read the [Authorship Guidelines](AUTHORSHIP.md) for more
+information.
+
+
 ## Reporting a Bug
 
 Find the *Issues* tab on the top of the Github repository and click *New Issue*.

MAINTENANCE.md

@@ -40,7 +40,7 @@ The main advantages of this are:
 
 ## Continuous Integration
 
-We use TravisCI and Azure Pipelines continuous integration (CI) services to build and 
+We use TravisCI and Azure Pipelines continuous integration (CI) services to build and
 test the project on Windows, Linux, and Mac.
 The configuration files for these services are `.travis.yml` and `.azure-pipelines.yml`.
 Both rely on the `requirements.txt` file to install the required dependencies using
@@ -78,15 +78,13 @@ file of your project. Then:
 
 1. Delete all existing files (they will be replaced with the new version).
 2. Reserve a DOI and save the release draft.
-3. Include as authors anyone who made contributions between now and the last release.
+3. Add as authors any new contributors who have added themselves to `AUTHORS.md`.
 
 On the other hand, if you're making the first release of the project, you need to create
 a **New upload** for it inside the
 [Fatiando a Terra community at Zenodo](https://zenodo.org/communities/fatiando/).
-
-1. Make sure the Fatiando a Terra community is chosen when filling the release draft.
-2. Reserve a DOI and save the release draft.
-3. Include as authors anyone who made contributions between now and the last release.
+Make sure the Fatiando a Terra community is chosen when filling the release draft.
+The rest of the process is the same as above.
 
 ### Updating the changelog
 
@@ -103,13 +101,14 @@ a **New upload** for it inside the
    to make the change automatically.
 4. Copy the remaining changes to `doc/changes.rst` under a new section for the
    intended release.
+5. Add a list of people who contributed to the release (use `git shortlog HEAD...v1.2.0 -sne`).
 5. Include the DOI badge in the changelog. Remember to replace your DOI inside the badge
    url.
 
     ```
-    .. image:: https://img.shields.io/badge/doi-<DOI-FIRST-PART>%2F<DOI-SECOND-PART>-blue.svg?style=flat-square
+    .. image:: https://zenodo.org/badge/DOI/<INSERT-DOI-HERE>.svg
         :alt: Digital Object Identifier for the Zenodo archive
-        :target: https://doi.org/<INSERT-YOUR-DOI>
+        :target: https://doi.org/<INSERT-DOI-HERE>
     ```
 
 6. Add a link to the new release version documentation in `README.rst`.

README.md

@@ -10,8 +10,9 @@ We also have an open Slack chat room for all of Fatiando at
 [contact.fatiando.org](http://contact.fatiando.org).
 
 This repository contains our standard [Contributing Guide](CONTRIBUTING.md),
-[Maintainers Guide](MAINTENANCE.md), and [Code of Conduct](CODE_OF_CONDUCT.md) that get
-copied to all Fatiando a Terra repositories.
+[Maintainers Guide](MAINTENANCE.md), [Authorship Guidelines](AUTHORSHIP.md),
+and [Code of Conduct](CODE_OF_CONDUCT.md) that get copied to all Fatiando a
+Terra repositories.
 
 Please feel free to use these files for your own projects.
 **If you make any changes that aren't specific to your project,