diff --git a/.travis.yml b/.travis.yml
new file mode 100644
index 00000000..9751bb4e
--- /dev/null
+++ b/.travis.yml
@@ -0,0 +1,37 @@
+os:
+  - linux
+  - osx
+sudo: required
+dist: trusty
+
+language: cpp
+compiler:
+  - gcc
+  - clang
+
+addons:
+  apt:
+    sources:
+    - xenial
+    - sourceline: 'deb http://archive.ubuntu.com/ubuntu xenial main'
+    packages:
+    - libjsoncpp-dev
+    - uuid-dev
+    - zlib1g-dev
+    - postgresql-all
+    - openssl
+    - libssl-dev
+    - build-essential
+    - cmake
+  homebrew:
+    packages:
+    - openssl
+    - cmake
+    - libtool
+    - lz4
+    - postgresql
+
+script:
+  - ./build.sh
+
+
diff --git a/orm_lib/inc/drogon/orm/Mapper.h b/orm_lib/inc/drogon/orm/Mapper.h
index 20bdd615..94c488db 100644
--- a/orm_lib/inc/drogon/orm/Mapper.h
+++ b/orm_lib/inc/drogon/orm/Mapper.h
@@ -37,6 +37,7 @@ class Mapper
     Mapper<T> &offset(size_t offset);
     Mapper<T> &orderBy(const std::string &colName, const SortOrder &order = SortOrder::ASC);
     Mapper<T> &orderBy(size_t colIndex, const SortOrder &order = SortOrder::ASC);
+    Mapper<T> &forUpdate();
 
     typedef std::function<void(T)> SingleRowCallback;
     typedef std::function<void(std::vector<T>)> MultipleRowsCallback;
@@ -102,11 +103,13 @@ class Mapper
     std::string _limitString;
     std::string _offsetString;
     std::string _orderbyString;
+    bool _forUpdate = false;
     void clear()
     {
         _limitString.clear();
         _offsetString.clear();
         _orderbyString.clear();
+        _forUpdate = false;
     }
     template <typename PKType = decltype(T::primaryKeyName)>
     typename std::enable_if<std::is_same<const std::string, PKType>::value, void>::type makePrimaryKeyCriteria(std::string &sql)
@@ -161,6 +164,10 @@ inline T Mapper<T>::findByPrimaryKey(const typename T::PrimaryKeyType &key) noex
     std::string sql = "select * from ";
     sql += T::tableName;
     makePrimaryKeyCriteria(sql);
+    if(_forUpdate)
+    {
+        sql += " for update";
+    }
     sql = _client->replaceSqlPlaceHolder(sql, "$?");
     clear();
     Result r(nullptr);
@@ -175,11 +182,11 @@ inline T Mapper<T>::findByPrimaryKey(const typename T::PrimaryKeyType &key) noex
     }
     if (r.size() == 0)
     {
-        throw Failure("0 rows found");
+        throw UnexpectedRows("0 rows found");
     }
     else if (r.size() > 1)
     {
-        throw Failure("Found more than one row");
+        throw UnexpectedRows("Found more than one row");
     }
     auto row = r[0];
     return T(row);
@@ -195,6 +202,10 @@ inline void Mapper<T>::findByPrimaryKey(const typename T::PrimaryKeyType &key,
     std::string sql = "select * from ";
     sql += T::tableName;
     makePrimaryKeyCriteria(sql);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     sql = _client->replaceSqlPlaceHolder(sql, "$?");
     clear();
     auto binder = *_client << sql;
@@ -202,11 +213,11 @@ inline void Mapper<T>::findByPrimaryKey(const typename T::PrimaryKeyType &key,
     binder >> [=](const Result &r) {
         if (r.size() == 0)
         {
-            ecb(Failure("0 rows found"));
+            ecb(UnexpectedRows("0 rows found"));
         }
         else if (r.size() > 1)
         {
-            ecb(Failure("Found more than one row"));
+            ecb(UnexpectedRows("Found more than one row"));
         }
         else
         {
@@ -224,6 +235,10 @@ inline std::future<T> Mapper<T>::findFutureByPrimaryKey(const typename T::Primar
     std::string sql = "select * from ";
     sql += T::tableName;
     makePrimaryKeyCriteria(sql);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     sql = _client->replaceSqlPlaceHolder(sql, "$?");
     clear();
     auto binder = *_client << sql;
@@ -235,7 +250,7 @@ inline std::future<T> Mapper<T>::findFutureByPrimaryKey(const typename T::Primar
         {
             try
             {
-                throw Failure("0 rows found");
+                throw UnexpectedRows("0 rows found");
             }
             catch (...)
             {
@@ -246,7 +261,7 @@ inline std::future<T> Mapper<T>::findFutureByPrimaryKey(const typename T::Primar
         {
             try
             {
-                throw Failure("Found more than one row");
+                throw UnexpectedRows("Found more than one row");
             }
             catch (...)
             {
@@ -277,6 +292,10 @@ inline T Mapper<T>::findOne(const Criteria &criteria) noexcept(false)
         sql = _client->replaceSqlPlaceHolder(sql, "$?");
     }
     sql.append(_orderbyString).append(_offsetString).append(_limitString);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     clear();
     Result r(nullptr);
     {
@@ -291,11 +310,11 @@ inline T Mapper<T>::findOne(const Criteria &criteria) noexcept(false)
     }
     if (r.size() == 0)
     {
-        throw Failure("0 rows found");
+        throw UnexpectedRows("0 rows found");
     }
     else if (r.size() > 1)
     {
-        throw Failure("Found more than one row");
+        throw UnexpectedRows("Found more than one row");
     }
     auto row = r[0];
     return T(row);
@@ -315,6 +334,10 @@ inline void Mapper<T>::findOne(const Criteria &criteria,
         sql = _client->replaceSqlPlaceHolder(sql, "$?");
     }
     sql.append(_orderbyString).append(_offsetString).append(_limitString);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     clear();
     auto binder = *_client << sql;
     if (criteria)
@@ -322,11 +345,11 @@ inline void Mapper<T>::findOne(const Criteria &criteria,
     binder >> [=](const Result &r) {
         if (r.size() == 0)
         {
-            ecb(Failure("0 rows found"));
+            ecb(UnexpectedRows("0 rows found"));
         }
         else if (r.size() > 1)
         {
-            ecb(Failure("Found more than one row"));
+            ecb(UnexpectedRows("Found more than one row"));
         }
         else
         {
@@ -348,6 +371,10 @@ inline std::future<T> Mapper<T>::findFutureOne(const Criteria &criteria) noexcep
         sql = _client->replaceSqlPlaceHolder(sql, "$?");
     }
     sql.append(_orderbyString).append(_offsetString).append(_limitString);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     clear();
     auto binder = *_client << sql;
     if (criteria)
@@ -359,7 +386,7 @@ inline std::future<T> Mapper<T>::findFutureOne(const Criteria &criteria) noexcep
         {
             try
             {
-                throw Failure("0 rows found");
+                throw UnexpectedRows("0 rows found");
             }
             catch (...)
             {
@@ -370,7 +397,7 @@ inline std::future<T> Mapper<T>::findFutureOne(const Criteria &criteria) noexcep
         {
             try
             {
-                throw Failure("Found more than one row");
+                throw UnexpectedRows("Found more than one row");
             }
             catch (...)
             {
@@ -400,6 +427,10 @@ inline std::vector<T> Mapper<T>::findBy(const Criteria &criteria) noexcept(false
         sql = _client->replaceSqlPlaceHolder(sql, "$?");
     }
     sql.append(_orderbyString).append(_offsetString).append(_limitString);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     clear();
     Result r(nullptr);
     {
@@ -433,6 +464,10 @@ inline void Mapper<T>::findBy(const Criteria &criteria,
         sql = _client->replaceSqlPlaceHolder(sql, "$?");
     }
     sql.append(_orderbyString).append(_offsetString).append(_limitString);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     clear();
     auto binder = *_client << sql;
     if (criteria)
@@ -459,6 +494,10 @@ inline std::future<std::vector<T>> Mapper<T>::findFutureBy(const Criteria &crite
         sql = _client->replaceSqlPlaceHolder(sql, "$?");
     }
     sql.append(_orderbyString).append(_offsetString).append(_limitString);
+    if (_forUpdate)
+    {
+        sql += " for update";
+    }
     clear();
     auto binder = *_client << sql;
     if (criteria)
@@ -967,6 +1006,12 @@ inline Mapper<T> &Mapper<T>::orderBy(size_t colIndex, const SortOrder &order)
     assert(!colName.empty());
     return orderBy(colName, order);
 }
+template <typename T>
+inline Mapper<T> &Mapper<T>::forUpdate()
+{
+    _forUpdate = true;
+    return *this;
+}
 
 } // namespace orm
 } // namespace drogon
diff --git a/trantor b/trantor
index e2cfbdab..1c96f8cf 160000
--- a/trantor
+++ b/trantor
@@ -1 +1 @@
-Subproject commit e2cfbdab4fcb3f6ef8e02a9a412ca5f7f1d663df
+Subproject commit 1c96f8cf24297a63e2e85428965a4247f262dbcf