feat: adds functions for setting a role for a user and retriving user roles

src/main/java/io/supertokens/storage/postgresql/Start.java

@@ -1450,14 +1450,32 @@ public int deleteUserMetadata(String userId) throws StorageQueryException {
     @Override
     public void addRoleToUser(String userId, String role)
             throws StorageQueryException, UnknownRoleException, DuplicateUserRoleMappingException {
-        // TODO
+
+        try {
+            UserRolesQueries.addRoleToUser(this, userId, role);
+        } catch (SQLException e) {
+            if (e instanceof PSQLException) {
+                PostgreSQLConfig config = Config.getConfig(this);
+                ServerErrorMessage serverErrorMessage = ((PSQLException) e).getServerErrorMessage();
+                if (isForeignKeyConstraintError(serverErrorMessage, config.getUserRolesTable(), "role")) {
+                    throw new UnknownRoleException();
+                }
+                if (isPrimaryKeyError(serverErrorMessage, config.getUserRolesTable())) {
+                    throw new DuplicateUserRoleMappingException();
+                }
+            }
+            throw new StorageQueryException(e);
+        }
 
     }
 
     @Override
     public String[] getRolesForUser(String userId) throws StorageQueryException {
-        // TODO
-        return new String[0];
+        try {
+            return UserRolesQueries.getRolesForUser(this, userId);
+        } catch (SQLException e) {
+            throw new StorageQueryException(e);
+        }
     }
 
     @Override

src/main/java/io/supertokens/storage/postgresql/queries/UserRolesQueries.java

@@ -134,4 +134,24 @@ public static String[] getRoles(Start start) throws SQLException, StorageQueryEx
         });
     }
 
+    public static int addRoleToUser(Start start, String userId, String role)
+            throws SQLException, StorageQueryException {
+        String QUERY = "INSERT INTO " + getConfig(start).getUserRolesTable() + "(user_id, role) VALUES(?, ?);";
+        return update(start, QUERY, pst -> {
+            pst.setString(1, userId);
+            pst.setString(2, role);
+        });
+    }
+
+    public static String[] getRolesForUser(Start start, String userId) throws SQLException, StorageQueryException {
+        String QUERY = "SELECT role FROM " + getConfig(start).getUserRolesTable() + " WHERE user_id = ? ;";
+
+        return execute(start, QUERY, pst -> pst.setString(1, userId), result -> {
+            ArrayList<String> roles = new ArrayList<>();
+            while (result.next()) {
+                roles.add(result.getString("role"));
+            }
+            return roles.toArray(String[]::new);
+        });
+    }
 }