Create rules for repository.

Follow the rules. Do not add new things into 'master' branch, but use
slapos one. It was used to introduce slapos component, and as repository
is about slapos, this place seems the best way to start explaining.

00.Repository.Rules.txt

+SlapOS repository rules
+=======================
+
+Short version for impatient
+---------------------------
+
+'master' branch is always stable. One shall never work in this branch. One
+shall expect reversion or removal of his commits in 'master' branch, if they
+are not because of merging another branch.
+
+Everyone has to create branch, basing on 'master' or any other branch. All
+work shall be done in such branch. It is advised to review it before merging
+into 'master'. It is very good habit to tag such merges.
+
+A bit more background
+---------------------
+
+SlapOS repository 'master' branch is supposed to be stable. No new work is
+accepted on this branch. Each time someone uses (clones, extends) 'master'
+branch it is supposed to work (as far as it was tested).
+
+Tags on 'master' branch are supposed to be repeatable software definitions
+forever. All versions and external links shall be setup in a way, that they
+wouldn't change in day, month, year, etc.
+
+Everyone can make his own branch to introduce new software to SlapOS. There
+are no rules about those branches, as each software is specific.
+
+It is good idea to ask for review before merging changes into 'master' branch.
+Peer review can detect issues not detected by testing, development or self
+analysis.
+
+After some software is stabilised and no more work is planned it is acceptable
+to remove such abandoned branch in order to minimise amount of branches.