add bootstrap to documentation

COPYING

+Copyright (C) 2012-2013, <ale@incal.net>.
+
+Permission is hereby granted, free of charge, to any person obtaining
+a copy of this software and associated documentation files (the
+"Software"), to deal in the Software without restriction, including
+without limitation the rights to use, copy, modify, merge, publish,
+distribute, sublicense, and/or sell copies of the Software, and to
+permit persons to whom the Software is furnished to do so, subject to
+the following conditions:
+
+The above copyright notice and this permission notice shall be
+included in all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
+EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
+MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
+NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
+LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
+OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
+WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.

README.rst

@@ -19,9 +19,18 @@ always going to be small enough to easily fit in an email message.
 Installation and Setup
 ======================
 
-It needs to be installed along with your main GPG secret key, as it
-will need to sign and decrypt data as yourself. Then, you need to find
-a way to feed certain messages from your INBOX to the `ssbm` tool.
+Once you have a proper Go environment set up, this should be enough::
+
+    $ go install git.autistici.org/ale/ssbm
+
+The software needs to be installed along with your main GPG secret
+key, as it will need to sign and decrypt data as yourself. For this
+reason, it is recommended that you use an agent (unless you want GPG
+to prompt you for the passphrase every single time you perform an ssbm
+operation).
+
+You need to find a way to feed certain messages from your INBOX
+to the `ssbm` tool (for the `receive` command).
 
 The program will look for the GnuPG executable as `gpg` in the current
 path, but you can override this by setting the `GNUPG` environment
@@ -53,13 +62,19 @@ Procmail, you can put the following rule in your `.procmailrc`::
     | /usr/bin/ssbm receive
 
 Messages intended for ssbm always have the `[SSBM]` string in the
-*Subject* header.
+*Subject* header. This cannot be modified for the moment, thus
+limiting usage to a *single* shared datastore! This is a bug that will
+be fixed soon.
 
 
 Step 3 (optional): Import bootstrap data
 ----------------------------------------
 
-TBD
+If you have just been added to the shared datastore (i.e. someone
+has run `add-friend` with your email and GPG key), you will have
+received an encrypted email with `[SSBM]` in the subject. Verify
+that the source is trusted and the signature is correct, decrypt
+the data and pipe it into `ssbm bootstrap`.
 
 
 Usage