Deck Implementation

Implemented a Deck type that has a new function that returns an
unshuffled deck. Also wrote an integration test for the new function to
make sure that it works.

Reviewed-on: #11

src/deck.rs

@@ -0,0 +1,41 @@
+use super::card::Card;
+
+pub struct Deck {
+    deck_size: u64,
+    current_card: u64,
+    cards: Vec<Card>,
+}
+
+impl Deck {
+    pub fn new(num_decks: u64) -> Self {
+        let deck_size: u64 = num_decks * 52;
+        let mut cards: Vec<Card> = Vec::new();
+
+        for card in 0..deck_size {
+            let value = (card % 13) as u8;
+            let suit = ((card / 13) % 4) as u8;
+
+            cards.push(Card {
+                value: value,
+                suit: suit,
+            });
+        }
+
+        Deck {
+            deck_size: deck_size,
+            current_card: 0,
+            cards: cards,
+        }
+    }
+
+    pub fn get_next_card(&mut self) -> Card {
+        let next_card = self.cards[self.current_card as usize];
+        self.current_card += 1;
+
+        next_card
+    }
+
+    pub fn deck_size(&self) -> usize {
+        self.deck_size as usize
+    }
+}