Added usage of Enum in basics-storing values page (#119)

* add example of string, hash and Enum

* add example of string, hash and Enum

* Update docs/basics/storing-values.md

* Update docs/basics/storing-values.md

Co-authored-by: Michael Müller <[email protected]>

docs/basics/storing-values.md

@@ -48,7 +48,39 @@ mod MyContract {
     /* --snip-- */
 }
 ```
+Here is an example of a structure storing `String` and  `Hash` values. 
 
+```rust
+pub struct Auction {
+    /// Branded name of the auction event.
+    name: String,
+    /// Some hash identifying the auction subject.
+    subject: Hash,
+    /// Auction status.
+    status: Status, // Enum: Usage shown in next section
+    /// Candle auction can have no winner.
+    /// If auction is finalized, that means that the winner is determined.
+    finalized: bool,
+    /// vector
+    vector: Vec<u8>,
+}
+```
+
+## Use of enum 
+
+Enum can be used as a datatype in `struct` as depicted above in `struct Auction`
+
+```rust
+pub enum Status {
+    /// An auction has not started yet.
+    NotStarted,
+    /// We are in the starting period of the auction, collecting initial bids.
+    OpeningPeriod,
+    /// We are in the ending period of the auction, where we are taking snapshots
+    /// of the winning bids. 
+}
+```
+The values of enum should be referenced as `Status::OpeningPeriod`
 ## Initializing Storage in Constructors
 
 Constructors are how values get initialized.