You can also generate this assembly using Sgen.exe
For me it's located in: C:\Program Files (x86)\Microsoft SDKs\Windows\v8.1A\bin\NETFX 4.5.1 Tools
1. open cmd command
2. cd yourProjectPath
3. sgen Project.dll
The following command creates an assembly named Project.XmlSerializers.dll for serializing all the types contained in the assembly named Project.dll.