Don't run torch.gen tasks at top-level of umbrella

When in an umbrella app, raise an error if any of the
torch.gen.* Mix tasks are run at the top-level instead of
in the app-specific level directories.

lib/mix/tasks/torch.gen.html.ex

@@ -13,6 +13,10 @@ defmodule Mix.Tasks.Torch.Gen.Html do
   @commands ~w[phx.gen.html phx.gen.context]
 
   def run(args) do
+    if Mix.Project.umbrella?() do
+      Mix.raise("mix torch.gen.html can only be run inside an application directory")
+    end
+
     %{format: format} = Mix.Torch.parse_config!("torch.gen.html", args)
 
     # First, backup the projects existing templates if they exist

lib/mix/tasks/torch.install.ex

@@ -21,6 +21,10 @@ defmodule Mix.Tasks.Torch.Install do
   """
 
   def run(args) do
+    if Mix.Project.umbrella?() do
+      Mix.raise("mix torch.install can only be run inside an application directory")
+    end
+
     %{format: format, otp_app: otp_app} = Mix.Torch.parse_config!("torch.install", args)
 
     Mix.Torch.copy_from("priv/templates/#{format}", [

lib/mix/tasks/torch.uninstall.ex

@@ -8,6 +8,10 @@ defmodule Mix.Tasks.Torch.Uninstall do
   """
 
   def run(args) do
+    if Mix.Project.umbrella?() do
+      Mix.raise("mix torch.uninstall can only be run inside an application directory")
+    end
+
     %{format: format, otp_app: otp_app} = Mix.Torch.parse_config!("torch.uninstall", args)
 
     paths = [