How we add all assets in our Web projects

your.csproj

<Project>
  <Target Name="BeforeBuild">
    <Exec WorkingDirectory="..\.." Command="powershell.exe .\grunt-build.ps1 -target $(Configuration)" />
    <ItemGroup>
      <Content Include="css\**\*.css" />
      <Content Include="js\**\*.js" />
      <Content Include="js\**\*.js.map" />
      <Content Include="fonts\**\*.*" />
      <Content Include="img\**\*.png" />
      <Content Include="img\**\*.gif" />
      <Content Include="img\**\*.jpg" />
      <Content Include="img\**\*.jpeg" />
      <Content Include="img\**\*.svg" />
      <Content Include="media\**\*.*" />
      <Content Include="usync\**\*.config" />
    </ItemGroup>
  </Target>
</Project>