docs: add namespace and relation naming conventions (#510)

docs/docs/concepts/namespaces.mdx

@@ -49,3 +49,32 @@ modify some storage specific options, it is required to manually review and run
 migrations on namespace configuration updates. Please refer to the
 [namespace migration CLI reference](/TODO) and
 [running in production guide](/TODO) to learn more about that process.
+
+## Naming Conventions
+
+Namespaces should be named after the plural of the type of objects they describe
+(e.g. `files`, `chats`, `organizations`). Relations within a namespace should be
+a word that describes what relation a subject has towards an object. As a rule
+of thumb, every relation tuple should translate to an english sentence like so:
+
+> **Subject** has **relation** on **object** which is one of the **namespace**.
+
+Examples:
+
+```keto-relation-tuples
+// good examples
+
+
+files:8f427c01-c295-44f3-b43d-49c3a1042f35#write@02a3c847-c903-446a-a34f-dae74b4fab86
+groups:43784684-103e-44c0-9d6c-db9fb265f617#member@b8d00059-b803-4123-9d3d-b3613bfe7c1b
+directories:803a87e9-0da0-486e-bc08-ef559dd8e034#child@(files:11488ab9-4ede-479f-add4-f1379da4ae43#_)
+files:11488ab9-4ede-479f-add4-f1379da4ae43#parent@(directories:803a87e9-0da0-486e-bc08-ef559dd8e034#_)
+
+// bad examples
+
+
+// namespace is not describing homogenous type of objects
+tenant-1-objects:62237c27-19c3-4bb1-9cbc-a5a67372569b#access@7a012165-7b21-495b-b84b-cf4e1a21b484
+// relation describes a relation of the object towards the subject
+directories:803a87e9-0da0-486e-bc08-ef559dd8e034#parent@(files:11488ab9-4ede-479f-add4-f1379da4ae43#_)
+```