Add route and API to set members of a group

src/groups.js

@@ -12,6 +12,7 @@ exports = module.exports = {
 
     getMembers: getMembers,
     addMember: addMember,
+    setMembers: setMembers,
     removeMember: removeMember,
     isMember: isMember,
 
@@ -203,6 +204,19 @@ function addMember(groupId, userId, callback) {
     });
 }
 
+function setMembers(groupId, userIds, callback) {
+    assert.strictEqual(typeof groupId, 'string');
+    assert(Array.isArray(userIds));
+    assert.strictEqual(typeof callback, 'function');
+
+    groupdb.setMembers(groupId, userIds, function (error) {
+        if (error && error.reason === DatabaseError.NOT_FOUND) return callback(new GroupError(GroupError.NOT_FOUND, 'Invalid group or user id'));
+        if (error) return callback(new GroupError(GroupError.INTERNAL_ERROR, error));
+
+        return callback(null);
+    });
+}
+
 function removeMember(groupId, userId, callback) {
     assert.strictEqual(typeof groupId, 'string');
     assert.strictEqual(typeof userId, 'string');