"dotnet-ef does not exist" in .net core heroku application - postgresql

Question

I am using jincod's Heroku .NET Core Buildpack to deploy my Core 3.1 MVC application to heroku.
Currently i am trying to apply EF migrations to postgre DB (using Npgsql) by executing command on publish:
<Target Name="PrePublishTarget" AfterTargets="Publish">
<Exec Command="dotnet tool install --global dotnet-ef" />
<Exec Command="dotnet ef database update" />
</Target>
Build fails with these messages:
You can invoke the tool using the following command: dotnet-ef
Tool 'dotnet-ef' (version '3.1.3') was successfully installed.
Could not execute because the specified command or file was not found.
Possible reasons for this include:
* You misspelled a built-in dotnet command.
* You intended to execute a .NET Core program, but dotnet-ef does not exist.
* You intended to run a global tool, but a dotnet-prefixed executable with this name could not be found on the PATH.
/tmp/build_35cf57c00fbf62634ac8d644c6e8f4f7/BugTracker.csproj(38,5): error MSB3073: The command "dotnet ef database update" exited with code 1.
! Push rejected, failed to compile ASP.NET Core app.
! Push failed
I explicitly install dotnet-ef, but for some reason it cannot find it?

Answer 1

You need to add "dotnet-tools.json". More info here https://github.com/jincod/dotnetcore-buildpack/pull/104