clean the meta, more tests, partial update of the docs

docs/relations/index.md

@@ -1,7 +1,64 @@
 # Relations
 
+Currently `ormar` supports two types of relations:
+
+* One-to-many (and many-to-one) with `ForeignKey` field
+* Many-to-many with `ManyToMany` field
+
+Below you can find a very basic examples of definitions for each of those relations.
+
+To read more about methods, possibilities, definition etc. please read the subsequent section of the documentation. 
+
 ## ForeignKey
 
+To define many-to-one relation use `ForeignKey` field.
+
+```Python hl_lines="17"
+--8<-- "../docs_src/relations/docs003.py"
+```
+
+!!!tip
+    To read more about one-to-many relations visit [foreign-keys][foreign-keys] section
+
 ## Reverse ForeignKey
 
-##ManyToMany
+The definition of one-to-many relation also uses `ForeignKey`, and it's registered for you automatically.
+
+So in relation ato example above.
+
+```Python hl_lines="17"
+class Department(ormar.Model):
+    class Meta:
+        database = database
+        metadata = metadata
+
+    id: int = ormar.Integer(primary_key=True)
+    name: str = ormar.String(max_length=100)
+    # there is a virtual field here like follows
+    courses: Optional[List[Course]] = ormar.ForeignKey(Course, virtual=True)
+    # note that you DO NOT define it yourself, ormar does it for you.
+```
+
+!!!tip
+    To read more about many-to-one relations (i.e changing the name of generated field) visit [foreign-keys][foreign-keys] section
+
+
+!!!tip
+    Reverse ForeignKey allows you to query the related models with [queryset-proxy][queryset-proxy].
+
+##ManyToMany
+
+To define many-to-many relation use `ManyToMany` field.
+
+
+!!!tip
+    To read more about many-to-many relations visit [many-to-many][many-to-many] section
+
+
+!!!tip
+    ManyToMany allows you to query the related models with [queryset-proxy][queryset-proxy].
+
+
+[foreign-keys]: ./foreign-key.md
+[many-to-many]: ./many-to-many.md
+[queryset-proxy]: ./queryset-proxy.md