README.md: Add compilation instructions

README.md

@@ -1,3 +1,36 @@
-deltamap
+DeltaMap
 ========
 A simple map viewer.
+
+Building
+--------
+DeltaMap is written in Rust, so you will need to [install
+Rust](https://www.rust-lang.org/install.html) to compile the program. The
+minimum supported version of Rust for DeltaMap is **1.25**.
+
+On Linux you will also need OpenSSL with headers.
+(see https://github.com/sfackler/rust-openssl for details)
+
+```sh
+# On Debian and Ubuntu
+$ sudo apt-get install pkg-config libssl-dev
+# On Arch Linux
+$ sudo pacman -S openssl
+# On Fedora
+$ sudo dnf install openssl-devel
+```
+
+Build and install the latest release from crates.io:
+
+```sh
+$ cargo install deltamap
+```
+
+Build the latest development version:
+
+```sh
+$ git clone https://github.com/b-r-u/deltamap
+$ cd deltamap
+$ cargo build --release
+$ ./target/release/deltamap
+```