Merge pull request #44 from rustcoreutils/docs

update CONTRIBUTING

CONTRIBUTING.md

@@ -14,7 +14,8 @@ There are several ways to contribute to posixutils-rs:
 3. Test coverage:  Integration tests, positive and negative, are complete, pass 100%
 4. Code coverage:  Automated code coverage data indicates 100%
 5. Translated:  All strings are internationalized, including common OS errors for common error cases.
-6. Audited:  An external party has reviewed and tested for POSIX compliance.
+6. Audited:  An external party has reviewed and tested for correctness, 
+   POSIX compliance, security, races and similar issues.
 
 ### Coding considerations
 
@@ -31,18 +32,24 @@ There are several ways to contribute to posixutils-rs:
 2. Ideal goal:  **Each utility should look like a standard Rust CLI program.** 
    Small, lightweight utility with command line processing,
    core algorithm, and zero external crate dependencies.
-3. "only std"  When an external crate is required, avoid mega-crates.  Prefer std-only, or, tiny
-   crates such as `atty` that perform a single, lightweight function.
+3. "only std"  When an external crate is required, avoid mega-crates.  Prefer
+   std-only, or, tiny crates such as `atty` that perform a single,
+   lightweight function.
 4. Correctness, readability, performance, in that order.
-   Code should be readable by unfamiliar developers.
-   Avoid dense, uncommented code.
+   Code should be readable by unfamiliar developers.  Avoid dense,
+   uncommented code.
 
-### Testing and POSIX compliance goals
+### Testing, POSIX compliance and programmaticgoals
 
 * All utilities should have tests.
 * Only "quick" tests should be run automatically in `cargo test`
-* Goal #1: POSIX compliance
-* Goal #2: Support the most popular Linux/BSD extesnsions
+* Longer tests, or tests requiring root access, should be triggered
+  via special environment variables.
+* POSIX compliance
+* Support the most widely used GNU/BSD extensions
+* If a system has an OS-specific feature that _must_ be
+  exposed through a given utility, do so.
+* Race-free userland.  `walker` crate should be able to help.
 
 ### Testing and Bug Reporting