Added getRoles method

src/main/java/com/moviesdb/DataBaseConnector.java

@@ -154,6 +154,30 @@ public class DataBaseConnector {
         return  resultedMovies;
     }
 
+    public List<Role> getRoles(int targetId) {
+        List<Role> roles = new ArrayList<Role>();
+
+        try {
+            Statement statement = conn.createStatement();
+            String req = "SELECT * FROM Roles WHERE movie_id=" + targetId + ";";
+            ResultSet rs = statement.executeQuery(req);
+            while (rs.next()) {
+                int id = rs.getInt("id");
+                int movieId = rs.getInt("movie_id");
+                String actor = Objects.requireNonNullElse(rs.getString("actor"), "");
+                String role = Objects.requireNonNullElse(rs.getString("role"), "");
+                Role entry = new Role(movieId, actor, role, id);
+                roles.add(entry);
+            }
+        }
+        catch (SQLException ex) {
+            //exception
+            ex.printStackTrace();
+            roles = null;
+        }
+        return  roles;
+    }
+
     public int addMovie(Movie movie) {
         try {
             Statement statement = conn.createStatement();