add .gitignore file

.gitignore

+# For checking that no file has been unduly ignored, run:
+# $ git ls-files -i --exclude-per-directory=.gitignore
+# Any file that is displayed should be removed from the ignore list
+# (possibly by an exclusion rule beginning with an exclamation mark)
+
+# Generic ignore rules
+*~
+*.o
+*.a
+*.fig
+\#*\#
+*.mat
+*.asv
+
+/missing_dbnomics
\ No newline at end of file