Improve README

README.md

@@ -4,7 +4,9 @@ Tini - A tiny but valid `init` for containers
 Tini is the simplest `init` you could think of.
 
 All Tini does is spawn a single child (Tini is meant to be run in a container),
-and wait for it to exit all the while reaping zombies.
+and wait for it to exit all the while reaping zombies and performing
+signal forwarding.
+
 
 Using Tini
 ----------
@@ -19,3 +21,28 @@ Once you've added Tini, use it like so:
 
 Note that you *can* skip the `--` above if your program only accepts
 positional arguments, but it's best to get used to using it.
+
+If you try to use positional arguments with Tini without using `--`, you'll
+get an error similar to:
+
+    ./tini: invalid option -- 'c'
+
+
+Understanding Tini
+------------------
+
+After spawning your process, Tini will wait for signals and forward those
+to the child process (except for `SIGCHLD` and `SIGKILL`, of course).
+
+Besides, Tini will reap potential zombie processes every second.
+
+
+Debugging
+---------
+
+If something isn't just like you expect, consider increasing the verbosity
+level (up to 3):
+
+    tini -v   -- bash -c 'exit 1'
+    tini -vv  -- true
+    tini -vvv -- pwd