feat(solution): problem #1

also added a gitignore line for macos file manager confs

.gitignore

@@ -0,0 +1,2 @@
+# macOS
+.DS_Store

solutions/001/multiplesof3or5.py

@@ -0,0 +1,7 @@
+sum = 0
+
+for i in range(1000):
+    if (i % 3) == 0 or (i % 5) == 0:
+        sum += i
+
+print("The sum of all the multiples of 3 or 5 is: %d" % (sum))