dev: php-tuf#398 Add DDEV config and developer documentation (php-tuf#399)

Author: star-szr

.ddev/config.yaml

@@ -0,0 +1,2 @@
+type: php
+docroot: ""

.gitattributes

@@ -25,3 +25,6 @@
 *.txt     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=4
 *.xml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=4
 *.yml     text eol=lf whitespace=blank-at-eol,-blank-at-eof,-space-before-tab,tab-in-indent,tabwidth=2
+
+# Exclude local development tools from packaging.
+/.ddev export-ignore

.gitignore

@@ -2,6 +2,7 @@ fixtures/**/client
 fixtures/**/server
 
 /vendor/
+/var
 .idea
 composer.lock
 .DS_Store

DEVELOP.md

@@ -0,0 +1,43 @@
+Developing PHP-TUF
+==================
+
+This project uses [DDEV](https://ddev.com) to standardize its local development environment. To get started, make sure that you have the [latest release](https://github.com/ddev/ddev/releases) of DDEV [installed](https://ddev.com/get-started/).
+
+## Initial setup
+
+```
+ddev start
+ddev composer install
+```
+
+## Running tests
+
+```
+ddev composer fixtures
+ddev composer test
+```
+
+To run a single test use PHPUnit's `--filter` option:
+```
+ddev exec phpunit ./tests --debug --filter=testEmptyStructuresAreEncodedAsObjects
+```
+
+### Checking code coverage
+
+```
+ddev xdebug
+ddev composer coverage
+```
+
+## Linting and fixing
+
+Linting for syntax, then style:
+```
+ddev composer lint
+ddev composer phpcs
+```
+
+Fixing style errors that can be automatically fixed:
+```
+ddev composer phpcbf
+```