Added crate description to Identity-did crate

identity-did/src/lib.rs

@@ -1,7 +1,20 @@
 // Copyright 2020-2021 IOTA Stiftung
 // SPDX-License-Identifier: Apache-2.0
 
-//! Types and traits for working with Decentralized Identifiers.
+//! Agnostic implementation of the Decentralized Identifiers (DID) standard from W3C.
+//! 
+//! Decentralized Identifiers (DID) is a proposed standard from the World Wide Web Consortium (W3C) to enable a verifiable and decentralized identity.
+//! The standard provides a unique identifier (DID), which can be used to look up more information about the associated identity in the form of a DID Document.
+//! The DID Document contains public keys, to prove control over the identity, and service endpoints which are URI's that can be resolved to find more public information about the identity.
+//! Often the DID Documents are stored on an Distributed Ledger Technology (DLT) such as Bitcoin, Ethereum and IOTA, but this is not a requirement.
+//! 
+//! This is an agnostic implementation of the [DID specifications v1.0 Working Draft 20200731](https://www.w3.org/TR/2020/WD-did-core-20200731/).
+//! 
+//! It has been implemented in the following DID Methods:
+//! 
+//! - [IOTA Identity](https://github.com/iotaledger/identity.rs/tree/dev/identity-iota): Developed and maintained by the IOTA Foundation, utilizing the IOTA Tangle.
+//! 
+//! See [our documentation portal](https://identity.docs.iota.org/overview/did.html) for additional documentations, conceptual explainations and usage examples. 
 
 #![warn(
   rust_2018_idioms,