Add upgrade instructions

docs/install.md

@@ -1,6 +1,6 @@
 # Installation
 
-The most simple way to try it out is to download precompiled binary for your OS. The most convenient way (in terms of regular updates) is to use Cargo.
+The most simple way to try it out is to download precompiled binary for your OS.
 
 Shell completion rules can be generated using `investments completion` command.
 
@@ -10,6 +10,8 @@ Shell completion rules can be generated using `investments completion` command.
 
 You can find precompiled binaries on [Releases](https://github.com/KonishchevDmitry/investments/releases) page.
 
+[binup](https://github.com/KonishchevDmitry/binup) can be used to keep your installed version up-to-date.
+
 ## Cargo
 
 1. Install Rust — https://www.rust-lang.org/tools/install