Don't allow quotes inside string

src/lexer.rs

 lazy_static! {
     static ref WHITESPACE_REGEX: Regex = Regex::new(r"\s").unwrap();
     static ref MATCHERS: Vec<Matcher> = vec![
-        Matcher::new(r#"^"(.*)""#, TokenType::String),
+        Matcher::new(r#"^"([^"]*)""#, TokenType::String),
         Matcher::new(r#"(?i)^SELECT"#, TokenType::Select),
         Matcher::new(r#"(?i)^FROM"#, TokenType::From),
         Matcher::new(r#"(?i)^WHERE"#, TokenType::Where),
         )
     }
 
+    #[test]
+    fn it_scans_two_strings() {
+        assert_eq!(
+            scan("\"hello\"  \"world\"").unwrap(),
+            vec![
+                Token::new(TokenType::String, "hello"),
+                Token::new(TokenType::String, "world"),
+            ]
+        )
+    }
+
     #[test]
     fn it_scans_uppercase_keywords() {
         assert_eq!(