some docs

README.md

@@ -2,4 +2,29 @@
 
 Install with `cargo install --git https://github.com/Nilstrieb/cargo-minimize` and use with `cargo minimize`.
 
-It's in a stage where it probably mostly works but is not very good and the output is unreadable if you don't know the internals.
+## Idea
+
+When encountering problems like internal compiler errors, it's often desirable to have a minimal reproduction that can be used by the people fixing the issue. Usually, these problems are found in big codebases. Getting from a big codebase to a small (<50 LOC) reproduction is non-trivial and requires a lot of manual work. `cargo-minimize` assists you with doing some minimization steps that can be easily automated for you.
+
+## How to use
+
+For minimizing an internal compiler error on a normal cargo project, `cargo minimize` works out of the box. There are many configuration options available though.
+
+```
+Usage: cargo minimize [OPTIONS] [PATH]
+
+Arguments:
+  [PATH]  The directory/file of the code to be minimited [default: src]
+
+Options:
+      --cargo-args <CARGO_ARGS>    Additional arguments to pass to cargo, seperated by whitespace
+      --no-color                   To disable colored output
+      --rustc                      This option bypasses cargo and uses rustc directly. Only works when a single file is passed as an argument
+      --no-verify                  Skips testing whether the regression reproduces and just does the most aggressive minimization. Mostly useful for testing an demonstration purposes
+      --verify-fn <VERIFY_FN>      A Rust closure returning a bool that checks whether a regression reproduces. Example: `--verify_fn='|output| output.contains("internal compiler error")'`
+      --env <ENV>                  Additional environment variables to pass to cargo/rustc. Example: `--env NAME=VALUE --env ANOTHER_NAME=VALUE`
+      --project-dir <PROJECT_DIR>  The working directory where cargo/rustc are invoked in. By default, this is the current working directory
+      --script-path <SCRIPT_PATH>  NOTE: This is currently broken. A path to a script that is run to check whether code reproduces. When it exits with code 0, the problem reproduces
+  -h, --help                       Print help information
+  ```
+