Missing installation instructions

[leo-hydraulic]

There aren't enough instructions on how to get the plugin up and running. We installed it on our Teamcity, but the build step doesn't run because none of the agents has the "Cargo_Path" parameter (env var?).

Reading the instructions very carefully, among the features provided by the plugin is "Rust toolchains installation via rustup".
However, there is no indication of how this feature is provided. If anything, there seems to be a strong implication that rustup needs to be installed in the agent for it to work.

If it is indeed the case that rustup must be pre-installed in the agent for the plugin to work, then:

1. It isn't clear;
2. There are no clear instructions on how to do it. The default installation of rustup sets up the rust/cargo folders under the user home dir, which doesn't sound appropriate for Teamcity.

[mikehearn]

Ignoring rustup for now, it's just a case of restarting the agent after installing rustc and cargo on the agent host (e.g. via apt-get).