Specify the minimum required Rust version in the manifest

Also mention it in the deployment guide.

Cargo.toml

@@ -8,6 +8,7 @@ repository = "https://gitlab.com/famedly/conduit"
 readme = "README.md"
 version = "0.1.0"
 edition = "2018"
+rust = "1.50"
 
 # See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
 

DEPLOY.md

@@ -6,7 +6,7 @@ If you run into any problems while setting up Conduit, write an email to `timo@k
 
 ## Installing Conduit
 
-You have to download the binary that fits your machine. Run `uname -m` to see
+You may simply download the binary that fits your machine. Run `uname -m` to see
 what you need. Now copy the right url:
 - x84_64: `https://conduit.rs/master/x86_64/conduit-bin`
 - armv7: `https://conduit.rs/master/armv7/conduit-bin`
@@ -18,6 +18,13 @@ $ sudo wget -O /usr/local/bin/matrix-conduit <url>
 $ sudo chmod +x /usr/local/bin/matrix-conduit
 ```
 
+Alternatively, you may compile the binary yourself using
+```bash
+$ cargo build --release
+```
+Note that this currently requires Rust 1.50.
+
+
 ## Adding a Conduit user
 
 While Conduit can run as any user it is usually better to use dedicated users for different services.