docs: Describe keystore and the alternative ways to set its location.

docs/IDENTITIES.md

@@ -36,7 +36,13 @@ const orbitdb = await OrbitDB({ identities, id: 'userA' })
 
 This identity can now be used by OrbitDB to control access to database actions such as write.
 
-##  Specifying a keystore
+## Key Store
+
+The key store is a local key manager for OrbitDB and is used to store the private keys generated by `Identities.createIdentity`. 
+
+[PublicKeyIdentityProvider](https://api.orbitdb.org/PublicKeyIdentityProvider) also uses key store to store the root key which is used to sign the identities created with `Identities.createIdentity`.
+
+###  Specifying a keystore
 
 An existing keystore can be passed to `Identities`:
 
@@ -49,6 +55,34 @@ const identities = await Identities({ keystore })
 const identity = identities.createIdentity({ id })
 ```
 
+### Customizing the key store path
+
+There are different ways to customize the location of the key store.
+
+To change the keystore using `OrbitDB`, pass a custom directory:
+```
+// This will create a key store under ./different-path/key-store
+const orbitdb = await OrbitDB({ directory: './different-path' })
+// Be aware that this will change the base path to the database as well.
+```
+
+To change the keystore using the KeyStore function, pass a custom path to the `KeyStore` function:
+```
+// This will create a key store under ./different-key-store.
+const path = ./different-key-store
+const keystore = await KeyStore({ path })
+
+// keystore can now be used with other functions, for example:
+const identities = await Identities({ keystore })
+```
+
+To specify a different keystore path using `Identities`, pass a custom path to the `Identities` function:
+```
+/// This will create a KeyStore under ./different-identities-path
+const path = ./different-identities-path
+const identities = await Identities({ path })
+```
+
 ## Identity as a linked data object
 
 The identity object is stored just like any other [IPLD data structure](https://ipld.io/docs/) and can therefore be retrieved from IPFS using the identity's hash: