Rename completion script

Author: Djuuu

README.md

@@ -110,7 +110,7 @@ _OR_
   	cg = "!bash /path/to/git-context-graph/git-context-graph"
   ```
 
-Completion is available in `.git-completion.bash`. Source it in one of your shell startup scripts:
+Completion is available in `git-context-graph-completion.bash`. Source it in one of your shell startup scripts:
 ```bash
-. "/path/to/git-context-graph/.git-completion.bash"
+. "/path/to/git-context-graph/git-context-graph-completion.bash"
 ```