write a quick doc on how to run a local dev net

documentation/en/local-dev-net.md

@@ -0,0 +1,29 @@
+# Running a local developer network
+
+Build the lotus binaries in debug mode, This enables the use of 1024 byte sectors.
+```
+make debug
+```
+
+Pre-seal some sectors:
+```
+./lotus-seed pre-seal --sector-size 1024 --num-sectors 2
+```
+
+Create the genesis block and start up the first node:
+```
+./lotus daemon --lotus-make-random-genesis=dev.gen --genesis-presealed-sectors
+=~/.genesis-sectors/pre-seal-t0101.json --bootstrap=false
+```
+
+Set up the genesis miner:
+```
+./lotus-storage-miner init --genesis-miner --actor=t0101 --sector-size=1024 --pre-sealed-sectors=~/.genesis-sectors --nosync
+```
+
+Now, finally, start up the miner:
+```
+./lotus-storage-miner run --nosync
+```
+
+If all went well, you will have your own local lotus network running!