add translation howto

share/qtcreator/translations/README

+How To add translations to Qt Creator
+=====================================
+
+- Coordinate over the mailing list to avoid duplicate work.
+
+- Add your language to the LANGUAGES line in translations.pro.
+  Don't qualify it with a country unless it is reasonable to expect
+  country-specific variants.
+  Skip this step if updating an existing translation, obviously.
+
+- Run "make ts". This will complain if you are not building against
+  Qt 4.6 (or the master branch which will become it).
+
+  If your Qt version is too old, you may create a template by running
+    lconvert --drop-translations qtcreator_de.ts -o qtcreator_<yours>.ts
+  and adjusting the language attribute in the new .ts file. The downside
+  of this method is obviously that you will not be translating the newest
+  Creator sources (unless qtcreator_de.ts was completely up-to-date).
+  Of course, this method is not applicable if you are updating an existing
+  translation.
+
+  You may also request an up-to-date template from us.
+
+  The remaining steps do *not* require Qt 4.6 in any case.
+
+- Fire up linguist and do the translation.
+
+- Check in the modified .pro file and _only_ your .ts file.
+
+- Make a merge request on gitorious.
+
+- .qm files are generated as part of the regular build.