expand README

README.md

@@ -21,6 +21,36 @@ Cargo-vcs is a Cargo extension that adds version control helpers to help manage
 
 - `cargo vcs profile set profile1`
 
+## Profile configs
+
+Profile config is saved in the workspace root directory under the name `Cargo_vcs.toml`. Manual editing is possible but using `cargo vcs profile save <profile_name>` is the preferred method as it resolves shortnames to full ref paths.
+
+### Profile format
+
+Toml file with the format of
+
+```toml
+[vcs.<profile_name>]
+<project_name> = "<git_reference>"
+...
+```
+
+## VCS support
+
+### Git
+
+Git is currently the only supported VCS.
+
+#### Uncommitted changes
+
+Profile and branch switching with uncommitted changes result in new stash pushes. Stashed changes are popped back when returning to the source reference or profile.
+
+Each stash change is saved under a specific name and looked up as such, FIFO is not used and stash changes created outside of cargo-vcs are not considered.
+
+### Others
+
+Currently only git is supported. Other version control systems can be added by implementing the `Repository` trait, however some more work is required in regards to the dirty changes strategy.
+
 ## Minimum Supported Rust Version (MSRV)
 
 This crate is guaranteed to compile on stable Rust 1.59.0 and up. It *might*