[doc] Add contribution.md and .gitmessage template

fix #29 (closed)

@keu-computervision PTAL

Documentation/.gitmessage

@@ -19,6 +19,7 @@
 #   * Can use multiple lines with "-" or "*" for bullet points in body
 # --------------------
 # Tag can be
+#
 #    feat       (new feature)
 #    fix        (bug fix)
 #    ci         (change to ci scripts)
@@ -27,15 +28,17 @@
 #    doc        (changes to documentation)
 #    test       (adding or refactoring tests; no production code change)
 #    version    (version bump/new release; no production code change)
-#    license    (Edits regarding licensing; no production code change)
+#    license    (edits regarding licensing; no production code change)
 #    perf       (improve code performance)
 #    defaults   (changes default options)
 #    submodule  (update one or several submodules)
 #    api        (break the public api)
 #    ui         (user interface change)
+#
 # Please avoid the following, but in case none of the above fit:
+#
 #    hack       (temporary fix to make things move forward)
-#    change     (default one)
+#    change     (in case none of the work)
 # --------------------