Add README and update usa start date (closes #10)

README.md

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+# govavailability.info
+
+Availability of the Government of the United States Of America.
+
+### How is availability defined?
+
+For purposes of this website, an outage is a period during which salaried Federal employees are prevented from executing their assigned duties due to a lapse in funding.
+
+### Why does the dataset not include shutdowns prior to 1980?
+
+There were no shutdowns prior to 1980. This is not to say that Congress never allowed appropriations to lapse, because of course they did. But it was only in 1980 that Attorney General Benjamin Civiletti interpreted the 1905 Antideficiency Act as requiring agencies to suspend operations during such a lapse.
+
+### What about the War of 1812 or [insert other _force majeure_ here]?
+
+People still got paid and did their jobs, even if their jobs now involved fleeing to Virginia.
+
+### Why does the dataset say the `usa` started on August 5, 1789?
+
+On this date, "An Act for settling the Accounts between the United States and individual States" was enacted by the first Constitutional Congress and President George Washington. The law allowed a commission on settling war debts, created by the Continental Congress, to hire "…a chief clerk, and such other clerks as the duties of their office may require; and that the pay of the said chief clerk be six hundred dollars per annum, and of each other clerk four hundred dollars per annum." This appears to be the earliest appropriation of funds for the purpose of paying employees of the Federal Government, and is thus considered the beginning of service availability.

data.json

@@ -1,6 +1,6 @@
 {
   "usa": {
-    "start": "1789-03-04T00:00:00-05:00",
+    "start": "1789-08-05T00:00:00-05:00",
     "end": null
   },
   "trump": {