Commit a25589c921 introduced an ignore line for ApplicationInsights.config. This change breaks builds on certain systems, namely VSTS.
The current ASP.NET 4 template adds ApplicationInsights.config to the project's .csproj file. When VSTS attempts to build the project, it will fail if it cannot find ApplicationInsights.config.
ApplicationInsights.config is a required application file and should not be ignored.
