add usage instructions

Author: greyltc

README.md

@@ -1,2 +1,24 @@
-# h5-peeker
+# analysis-toolkit
 a tool for peeking at beam diagnostic data in a hdf5 file
+
+## CLI interface usage
+```
+$ ./cli.py --help
+usage: cli.py [-h] [--draw-plots] [--no-spot-fit] [--database DATABASE]
+              [--freeze-file FREEZEOBJ] [-v]
+              [input [input ...]]
+
+Peek at beam diagnostic data in hdf5 files
+
+positional arguments:
+  input                 File(s) to process
+
+optional arguments:
+  -h, --help            show this help message and exit
+  --draw-plots          Draw analysis plots or each file processed
+  --no-spot-fit         Do not fit camera data to 2D gaussian
+  --database DATABASE   Save/append analysis data to this sqlite database file
+  --freeze-file FREEZEOBJ
+                        Freeze/draw data to a .csv file
+  -v, --verbose         Dump everything to the terminal during analysis
+```