Nest development docs into development/environment section.

docs/development/environment/composer.md

@@ -37,7 +37,7 @@ If the module is being added to the farmOS installation profile itself, you
 need to manually move the `require` line from the root `composer.json` to
 `web/profiles/farm/composer.json` and commit it to that repository.
 
-To install the module, use [Drush](/development/drush).
+To install the module, use [Drush](/development/environment/drush).
 
 ## Notes
 

docs/development/environment/debug.md

@@ -32,7 +32,7 @@ execution at your breakpoint.
 
 ### Drush + PHPStorm
 
-Debugging code that is run via [Drush](/development/drush) commands requires
+Debugging code that is run via [Drush](/development/environment/drush) commands requires
 additional configuration. Add `idekey=PHPSTORM` to the `XDEBUG_CONFIG`
 environment variable, and add a `PHP_IDE_CONFIG` environment variable with
 `serverName=localhost`, as follows:

docs/development/environment/index.md

@@ -40,4 +40,4 @@ In order to upload files, the following line must be added to
 
 ### Configure debugger
 
-See [Debugging](/development/debug).
+See [Debugging](/development/environment/debug).

mkdocs.yml

@@ -7,12 +7,13 @@ nav:
     - Introduction: api/index.md
     - Changes: api/changes.md
   - Development:
-    - Getting started: development/index.md
-    - Docker: development/docker.md
-    - PostgreSQL: development/postgresql.md
-    - Drush: development/drush.md
-    - Composer: development/composer.md
-    - Debugging: development/debug.md
-    - Automated tests: development/tests.md
-    - Coding standards: development/code.md
+    - Environment:
+      - Getting started: development/environment/index.md
+      - Docker: development/environment/docker.md
+      - PostgreSQL: development/environment/postgresql.md
+      - Drush: development/environment/drush.md
+      - Composer: development/environment/composer.md
+      - Debugging: development/environment/debug.md
+      - Automated tests: development/environment/tests.md
+      - Coding standards: development/environment/code.md
 theme: readthedocs