Add protection against WSL 2 using all your memory

At the time of writing this commit there's a pending issue for WSL 2
where it happily eats all of your memory over time.

Details are at: microsoft/WSL#4166

I ran into this issue naturally starting and stopping Docker containers
for half a day while doing my normal work. Before I knew it, the VM was
using 11GB of memory (the default is to use 80% of your RAM).

I'm not going to bikeshed on this by making a cronjob run the alias
command on a schedule because I imagine this will be fixed in a hotfix
at some point in the future.

Just be mindful of this if you notice that the Vmmem process is using a
ton of memory.

.aliases

@@ -61,3 +61,8 @@ alias 755d="find . -type d -exec chmod 755 {} \;"
 alias 644f="find . -type f -exec chmod 644 {} \;"
 
 alias open="/c/Program\ Files\ \(x86\)/Google/Chrome/Application/chrome.exe"
+
+# This is specific to WSL 2. If the WSL 2 VM goes rogue and decides not to free
+# up memory, this command will free your memory after about 20-30 seconds.
+#   Details: https://github.com/microsoft/WSL/issues/4166#issuecomment-628493643
+alias drop_cache="sudo sh -c \"echo 3 >'/proc/sys/vm/drop_caches' && swapoff -a && swapon -a && printf '\n%s\n' 'Ram-cache and Swap Cleared'\""

c/Users/Nick/.wslconfig

@@ -0,0 +1,9 @@
+[wsl2]
+memory=6GB                  # Make sure you have this amount available to use!
+swapFile=E:\\wsl2-swap.vhdx # I put mine off my SSD, but this is optional.
+
+# Another option is to disable swap but if the VM goes out of memory, the
+# OOM killer might start killing important processes or the VM may crash.
+#
+# Uncomment the line below this to use no swap file at all in the WSL 2 VM.
+#swap=0