improve related tags, merge Enterprise Resource Planning with Resource Planning (#305)

tags/games---administrative-utilities--control-panels.yml

@@ -1,2 +1,4 @@
 name: Games - Administrative Utilities & Control Panels
 description: Utilities for managing game servers.
+related_tags:
+  - Games

tags/games.yml

@@ -1,2 +1,4 @@
 name: Games
 description: Multiplayer game servers and [browser games](https://en.wikipedia.org/wiki/Browser_game).
+related_tags:
+  - Games - Administrative Utilities & Control Panels

tags/inventory-management.yml

@@ -6,4 +6,3 @@ external_links:
 related_tags:
   - Money, Budgeting & Management
   - Resource Planning
-  - Resource Planning - Enterprise Resource Planning

tags/money-budgeting--management.yml

@@ -2,4 +2,4 @@ name: Money, Budgeting & Management
 description: '[Money management](https://en.wikipedia.org/wiki/Money_management) and budgeting software.'
 related_tags:
   - Inventory Management
-  - Resource Planning - Enterprise Resource Planning
+  - Resource Planning

tags/resource-planning---enterprise-resource-planning.yml

@@ -1,2 +0,0 @@
-name: Resource Planning - Enterprise Resource Planning
-description: Software and tools to help with [enterprise resource and supply planning](https://en.wikipedia.org/wiki/Enterprise_resource_planning).

tags/resource-planning.yml

@@ -1,2 +1,5 @@
 name: Resource Planning
-description: Software and tools to help with [resource and supply planning](https://en.wikipedia.org/wiki/Resource_planning).
+description: Software and tools to help with [resource and supply planning](https://en.wikipedia.org/wiki/Resource_planning), including [enterprise resource and supply planning (ERP)](https://en.wikipedia.org/wiki/Enterprise_resource_planning).
+related_tags:
+  - Money, Budgeting & Management
+  - Inventory Management