Add DIA Wasm Oracle to Build section (#425)

docs/build/integrations/oracles/dia-wasm.md

@@ -0,0 +1,76 @@
+# DIA Wasm Oracle
+## Introduction
+DIA has a dedicated Wasm-based oracle. It can be universally deployed on any chain that supports substrate Wasm environment.
+
+## Prerequisites
+Make sure the version of ink you are on is v3.0.1.
+
+## Getting started
+To access values from DIA wasm oracles you need to copy the diadata directory to your contract so that you can access DIA structs, that contain the oracle data.
+
+### Contract Integration
+In your contract, create storage with DiaDataref, this is used to access values from the oracle.
+
+```
+    #[ink(storage)]
+    pub struct OracleExample {
+        diadata: DiadataRef,
+        ....
+        ....
+    }
+```
+
+This struct can be used to access data from pub functions from the oracle contract.
+
+### Link the contract with an Oracle
+To instantiate a contract's access to the oracle you need to pass the DIA oracle address, either using the constructor or by creating a separate write function to update with the value of oracle at a later stage.
+
+Here is an example using a constructor:
+
+```
+    #[ink(constructor)]
+    pub fn new(
+        oracle_address: AccountId, 
+    ) -> Self {
+        let diadata: DiadataRef = ink_env::call::FromAccountId::from_account_id(oracle_address);  
+        Self {
+            diadata
+        }
+    }
+```
+
+Here, `oracle_address` refers to the DIA oracle address of a deployed oracle contract.
+
+### Access the value
+Next, to access an oracle value you can simple call the get() function:
+
+```
+ pub fn get(&self ) -> diadata::ValueTime {
+            return self.diadata.get(String::from("ETH"));
+        }
+```
+
+This returns the ETH price value time given by the oracle.
+
+### Config changes
+
+Make sure you add diadata/std in you config:
+
+```
+std = [
+    "ink_metadata/std",
+    "ink_env/std",
+    "ink_storage/std",
+    "ink_primitives/std",
+    "scale/std",
+    "scale-info/std",
+    "diadata/std",
+]
+```
+
+## Addresses
+**Astar Wasm Smart Contract**: [XmVR4FbKWLYQgyHVxkFiBYScVo662WgSCoS84uZZPWNrtRT](https://shiden.subscan.io/account/XmVR4FbKWLYQgyHVxkFiBYScVo662WgSCoS84uZZPWNrtRT)
+**Shibuya Wasm Smart Contract**: [X5NLwAUYX7FwVk25a8JwaXtuVJQsW87GQcKxYoF3aLyu8Pz](https://shibuya.subscan.io/account/X5NLwAUYX7FwVk25a8JwaXtuVJQsW87GQcKxYoF3aLyu8Pz)
+
+## Learn more
+See the entire oracle code and instructions on how to run and oracle service by yourself in [our github repo](https://github.com/diadata-org/dia-wasm-oracle).